TECHNICAL REPORT

CONTENTS
11. Profile. 3 12. Features. 4 13. Front and rear panel. 7 3-1 Front panel 3-2 Rear panel 14. What is DSP in radio Communication?. 10 15. Circuit description. 12 5-1 Digital IF filter 5-2 Digital functions 5-3 PSN modulation 5-4 Manual notch 5-5 Speech compressor 5-6 Microphone equalizer 5-7 RTTY demodulator 5-8 Receiver 5-9 Transmitter 5-10 Dual-watch function 5-11 Real-time spectrum scope 5-12 Voice record/playback function 5-13 PLL circuit 16. Connection to option/peripheral units. 25 6-1 ACC Sockets 6-2 HF/50MHz, 1kW linear amplifier 6-3 Interface for digital mode 6-4 External control unit for voice memory keyer 6-5 Installation of UT-102 optional Voice Synthesizer Unit 17. CI-V control. 28 7-1 Remote jack 7-2 Data format of CI-V 7-3 List of commands 18. Inside Views. 32 19. Options. 33 10. Specifications. 34 10-1 General 10-2 Transmitter 10-3 Receiver 10-4 Antenna tuner 11. Block diagram. foldout
The IC-756PROII is the high performance HF transceiver of choice for todays discriminating amateur radio operator. Icoms engineers took cutting-edge digital technology and paired it with Icoms extensive experience with analog technology. The result is a major advancement of Icoms original digital IF filter which, in the earlier IC-756PRO model, enjoyed a great reputation around the world. The IC-756PROII uses the same 32-bit floating point DSP and a 24-bit A/D-D/A converter as the IC756PRO. It is now possible to execute the digital IF filter, noise reduction and the digital IF filter in the AGC loop processing, and to select the soft/sharp filter shapes. The IC-756PROII employs exclusive DSP/analog circuit matching to further improve receiver performance. Icoms engineers analyzed the influence of the AGC loop upon the received audio, matching it to an analog circuit suitable for the dynamic range of the A/D converter and the other parts used, and also re-examined the core stage of the receiver (ranging from RF top to mixer circuit), to distribute the mixer levels properly. As a result, the matching of digital and analog technology has attained a level never before achieved. This technical report does not explain in depth all the digital engineering with its many calculations and formulas. Instead, it focuses on the DSP engineering in an easy-to-understand manner. This report also explains why the 32-bit floating point DSP and 24-bit A/D-D/A converter are included. The dynamic range of the 32-bit floating point DSP and the 24-bit A/D-D/A converter may seem to be an over specification for amateur radio. But this is not the case. This technical report helps clarify these points. It is Icoms hope that in providing you with this report you will discover the IC-756PROIIs many digital advantages. Enjoy!

2. Features

32-bit floating point DSP and 24-bit A/D-D/A converter
The adoption of a 32-bit floating point DSP and 24-bit A/D-D/A converter in the IF stage (36kHz) was originally developed by Icom. It enables various digital functions which amateur radio operators desire. I 51 types of digital IF filtering The digital IF filter has superior filtering performance and a distinguished shaping factor that demonstrates the power of 32-bit floating point DSP. The digital filter is completely free from deterioration due to deviations in band characteristics, temperature change, or mechanical vibration, all of which have been observed in analog filters. It also provides excellent ripple characteristics that have never been available with analog filters. The passband (50Hz3.6kHz) of the digital IF filters used for IC-756PROII come in 51 types. This function allows 3 of these 51 types to be pre-set for each mode and to be changed instantaneously by using the filter button, depending on the situation. I 2 types of filter shape (Sharp/Soft) Changing the IF filter shape is a feature that is not available with analog radios. Select the filter shape from two types, Sharp and Soft, depending on the purpose, operating band, band conditions, etc. It is possible to set CW and SSB filter characteristics independently and also select the filter shape while actually receiving a signal. I Digital IF filter in AGC loop The digital IF filter, manual notch filter, etc. are located in the AGC loop, using DSP, which completely eliminates interference from adjacent strong signals. This allows the AGC to be operated only on the selected frequency. It is also possible to pre-set the operation of AGC in each mode in accordance with 13 types of time constants.

455 kHz 36 kHz

I Manual notch with superior attenuation level The IC-756PROIIs manual notch filter has extremely sharp characteristics for processing in the DSP and provides tremendous performance for attenuation levels >70dB. Analog notch circuits are susceptible to fluctuations in attenuation or changes in temperature. The DSP-based manual notch provides stable performance and is not susceptible to such changes. Also, the DSP signal processing executed within the AGC loop completely shuts off undesirable signals, even with the AGC set to high speed. An automatic notch is included to further enhance receiver performance. I Demodulator/decoder for RTTY This transceiver is equipped with a demodulator and a decoder for BAUDOT RTTY as a standard feature. On-air station calls may be recognized instantaneously by reading the received RTTY message directly on the IC-756PROIIs LCD no personal computer or external components are required. The transceiver is fitted with an on-screen tuning indicator that allows the RTTY to be fine tuned with ease. A DSP based twin-peak audio filter further improves the S/N ratio. This filter will reduce interference that appears between each tone (mark and space), which cannot be removed by conventional analog filters. This twin-peak audio filter works to capture noise-level signals accurately and to significantly reduce the generation of RTTY reception screen noise distortion. I New-generation speech compressor The DSP based speech compressor enhances the readability of your transmitted signal at a receiving station without any distortion, even when the compression is set to a high level. The gradation of voice processing is extremely close to the original sound. This assures superior sound quality at all compression levels.

The best in operating convenience and features
I Dual-watch Dual-watch enables simultaneous two-frequency receive in the same band, providing identical band and filter configurations in both receive systems. This makes it possible to receive two signals simultaneously as if two separate receivers are being used. This greatly enhances split frequency operation; enjoy enhanced DX-operation by searching for pickup frequencies while watching the transmit frequency of a DX station experiencing pile-up. Or have a QSO while simultaneously monitoring a DX net. I Triple band stacking register With the push of a band button, get quick memory recall of three preferred operating settings (including antenna port) per band. Band or mode hopping has never been easier. Its the ultimate in multimode flexibility. I Digital Voice Recorder (DVR) The DVR feature is an indispensable function for DX hunting and contests. The IC-756PROII is equipped with a DVR with 4 channels for transmit and 4 channels for receive, for a total of 8 channels. High quality digital mapping of the transmitted or received analog signal provides high quality audio reproduction, resulting in a natural sounding voice without any noticeable degradation. It is also possible to use these 4 communication channels by allotting them freely with a total recording time of 90 seconds. Each of the 4 channels for receive has a recording time of 15 seconds, or 60 seconds total. Press the key once in any TFT display mode and it becomes possible to not only record or reproduce voice but also to record for up to 30 minutes continuously. The receive audio may be reproduced for the most recent 15 seconds back to an interruption in recording. By constructing the simplified control unit (page 26) and connecting it to the microphone connector, digital voice recorder function may also be operated. I Full-scale electronic keyer Plug a CW, iambic paddle into the electronic keyer jack on the front panel. Especially handy during long hours of operation, it is possible to set the CW speed between 7 and 56WPM. The discriminating operator may also set the dot/dash keying ratio (2.8:1 to 4.5:1) and polarity, depending on preference. The keyer may also be set for either right or left hand use. For the CW operator who prefers not to use the IC-756PROIIs built-in electronic keyer, an ordinary key jack is available on the rear panel, for bug or straight key and is fully compatible with external keyers or PC keying. I Multi-function memory keyer Enhance your contest operations. The IC-756PROII is fully equipped with a convenient memory keyer, offering features such as memory content editing function, auto-repeat function, serial contest number automatic count-up function, contest number abbreviating function, and more. These features will reduce effort when repeating a formatted contents for calling CQ, continuous transmission of call sign, or contests. Since it is possible to confirm the contents of memory on the display, transmission mistakes are eliminated. Construct the simplified control unit (page 26) and connect it to the microphone connector to enhance operation of these memory keyer functions.

3. Front and rear panel

3-1 Front panel
POWER SWITCH [POWER TIMER] S/RF METER TRANSMIT SWITCH [TRANSMIT] HEADPHONE JACK [PHONES] ANTENNA TUNER SWITCH [TUNER] MONITOR SWITCH [MONITOR] NOISE BLANKER SWITCH [NB] NOISE REDUCTION SWITCH [NR]
ELECTRONIC KEYER JACK [ELEC-KEY]
AF CONTROL [AF] RF GAIN CONTROL/SQUELCH CONTROL [RF/SQL] BALANCE CONTROL [BAL] NOISE REDUCTION LEVEL CONTROL [NR] MICROPHONE CONNECTOR [MIC] MIC GAIN CONTROL [MIC GAIN] RF POWER CONTROL [RF POWER] COMPRESSION LEVEL CONTROL [COMP] SEMI BREAK-IN DELAY CONTROL [BK-IN DELAY] ELECTRONIC CW KEYER SPEED CONTROL [KEY SPEED]
LCD FUNCTION SWITCHES [F1]-[F5] MODE SWITCHES FILTER SWITCH [FILTER] EXIT/SET SWITCH [EXIT/SET]
MULTI-FUNCTION SWITCH GUIDE LCD FUNCTION DISPLAY
KEYPAD MEMORY UP/DOWN SWITCHES [ ][ ] MEMORY WRITE SWITCH [MW] MEMORY CLEAR SWITCH [M-CL] QUICK TUNING SWITCH [TS] TRANSMIT FREQUENCY CHECK SWITCH [XFC] MEMO PAD-READ SWITCH [MP-R] MEMO PAD-WRITE SWITCH [MP-W] MAIN/SUB CHANGE SWITCH [CHANGE] VFO/MEMORY SWITCH [VFO/MEMO] MAIN/SUB CHANGE SWITCH [CHANGE] DUALWATCH SWITCH [DUALWATCH] SPLIT SWITCH [SPLIT]
RECEIVE INDICATOR [RX] TRANSMIT INDICATOR [TX] REC/PLAY SWITCH [REC/PLAY] LOCK/SPEECH SWITCH [LOCK/SPEECH] TUNING DIAL LOCK INDICATOR [LOCK]
PASSBAND TUNING CONTROLS [TWIN PBT] PBT CLEAR SWITCH [PBT CLR] NOTCH SWITCH [NOTCH] MANUAL NOTCH FILTER CONTROL [NOTCH] CW PITCH CONTROL [CW PITCH] TX SWITCH [ TX] RIT SWITCH [RIT] RIT/ TX CONTROL [RIT/ TX] CLEAR SWITCH [CLEAR]

3-2 Rear panel

ACC (1)

ACC (2)

GROUND TERMINAL ANTENNA CONNECTOR 1 [ANT 1]/ ANTENNA CONNECTOR 2 [ANT 2] DC POWER SOCKET [DC 13.8V] SEND CONTROL JACK [SEND] ALC INPUT JACK [ALC] EXTERNAL SPEAKER JACK [EXT SP]
CI-V REMOTE CONTROL JACK [REMOTE] STRAIGHT KEY JACK [KEY] ACCESSORY SOCKET 1 [ACC (1)]/ ACCESSORY SOCKET 2 [ACC (2)] TUNER CONTROL SOCKET [TUNER] RECEIVE ANTENNA CONNECTOR [RX ANT] TRANSVERTER JACK [XVERT]
4. What is DSP in radio communication?
The term DSP stands for digital signal processor. When DSP is used in a communication unit, the electrical signal processes (amplification, filtering mixer, modulation, demodulation, etc.) are handled by the DSP. Such signal processing, using numerical calculations, is called digital signal processing. Digital signal processing assures the same results every time providing for the characteristics defined in the design phase. When digital signal processing is utilized, it is not necessary to take the adjustment deviations of the conventional analog circuit into consideration. These deviations are caused by variations in component characteristics, temperature change, or deterioration over time. It is also possible to perform complicated processing tasks such as Fourier transformation, adaptive control, special function processing (*1), and more. Such complicated processing tasks are very difficult and costly for a conventional analog circuit.

*1 Special function processing: Trigonometric function, inverse function of trigonometric function, square root, logarithmic function, exponential function, etc.
Background to development of the first-generation IC-756PRO
From the early stages of research into DSP transceivers Icom has been on the forefront of shifting IF filter design from analog to digital type filters. To put the digital IF filter to practical use it was necessary to incorporate the digital IF filter into the AGC loop. It was also necessary to provide AGC processing using the DSP. To achieve this there remained a lot of technical problems to be resolved. In the initial stage of research, it was not possible to complete the DSP, A/D, and D/A devices in a radio unit at a practical cost, as shortage in device capacity was a significant factor. Icom conducted research into digital PSN modulation, noise reduction, automatic notch, and audio peak filter, while also proceeding with research into digital IF filter processing and digital AGC processing. This research includes the ultra-narrow filter for CW that allows the advantages of DSP to be fully utilized for commercialization of a DSP transceiver. As the first devices were developed with improved capacity, Icom started full-scale research into integrating the digital IF filter processing (*2) and digital AGC processing in practical applications.
*2 Advantages of digital IF filter processing: Since a digital IF filter is free from deterioration due to passband width deviations, temperature changes, change in mechanical strength, etc., the changes seen in an analog filter will not occur. It will not deteriorate through years of use and will provide excellent ripple characteristics that are not possible with analog filters.
Digital signal processing is also widely used in fields other than radio communication units, such as: Modems for telephone circuits Surround-sound effects (stereo sets, stereo components) Echo canceller (telephone) Voice compression/coding (cellular phones) It is possible for a computer CPU to execute digital signal processing. However, a DSP differs from a CPU in that it has the dedicated hardware construction required for the effective execution of digital signal processing. Basically the unit has a multiplication/addition circuit widely used for DSP to execute the combination of multiplications and additions in one clock, and with an internal data bus of more than two circuits, to fetch two data items required for calculation at the same time. It also has a loop processing function to execute repeated calculations with high efficiency and a data address creation function to transmit signal data effectively, which are assigned to consecutive addresses. These functions are incorporated as dedicated hardware. Because their performance has developed quickly, the CPUs currently used for computers can execute digital signal processing. A CPU with a high clock frequency may be superior in calculation performance to a low-end DSP chip. When it is compared with a CPU of equivalent performance, a DSP with hardware specialized to digital signal processing has the following advantages: Low clock frequency Low integrity (reduced logic scale) Low power consumption (Low heat energy generated) Low cost When various judgment functions are required, or when different calculations are repeated each time, a DSP is not suitable. The CPU is then more suitable for such processing.

If the receive frequency is substituted for fRX, the input frequency for f 1 and the input frequency for f 2 respectively, the following relationship is established for 3rd order distortion component. ff2 = fRX, or f1 f= fRX If there are inputs of 14.2MHz and 14.3MHz while 14.1MHz is being received, the distortion component is heard at 14.1MHz. The relative value of the input level when the signal can be heard at 14.1MHz and the level of the signal received at the essential receive frequency is called the dynamic range. Figure 1 shows an example in which the following are plotted on the same axis. Input/output characteristics at receive frequency, or the characteristic data (a) for a case when the receive frequency component input from the ANT is detected and output as a low frequency signal Input level of frequency component (generating 3rd order distortion from the receive frequency) and level (b) at which the distortion can be heard at the receive frequency. The difference in level at which (a) and (b) above can be heard is the dynamic range. The level at intersecting point between (a) and (b) above is called IP3 (3rd order intercept point). If these numerical values are large, it can be said that signal processing is executed without distortion. When the numerical values are small, a frequency component that does not exist in the essential receive frequency is heard and distortion will be generated.
Since the level of scaling required is also increased to provide an IF filter with a sharp shape factor the calculation accuracy is liable to be decreased, even if double-precision (32-bit fixed decimal point) calculation is executed when using a high-speed 16-bit DSP. To provide both the digital IF filter processing and digital AGC processing using DSP, Icom determined it was necessary to use a 32-bit floating point DSP. For a 32-bit floating point DSP, the numerical data within the DSP is adjusted automatically according to the size of the numerical value. Consequently, errors generated due to calculation are extremely limited and the influence of calculation errors is almost negligible. Because it is not necessary to consider the overflow during calculation, the dynamic range will not be decreased due to the scaling operation. The 32-bit floating point DSP and 24-bit A/D-D/A converter use a signal processing algorithm (newly developed to demonstrate its performance) in combination for the reasons above, which make it possible to provide highly accurate digital IF filter processing and digital AGC processing. These new functions (FM demodulation, AM modulation/demodulation, RTTY modulator, etc.) were incorporated in the IC-756PRO to make it an IF DSP radio.

Dynamic range for A/D converter
Consider the dynamic range (used as an index for the performance of an A/D converter) as the ratio between maximum value and minimum value to be treated by the A/D converter. If the maximum resolution for one bit is Vmax in the case of a 16-bit A/D converter, the following is given: Vmax 216 = Vmax 65536 In other words, the change in level for one bit is 1/65536 of Vmax. This value seems to be an extremely small value, in decibels it will be as follows: 20log (1/65536) = 96.33dB This means that an S/N ratio of over 96dB is never allowed for transmit. The minimum resolution of signal the A/D converter can treat is affected by its specifications, which are 24 bits and 144dB logical value. Some may say that a transceiver is not a high-grade audio system and therefore does not require a specification of 144dB, or that a specification of 96dB is sufficient; however this value is not an over specification. If there is no AGC in the DSP and the input level of the A/D converter is properly controlled by the analog circuit AGC, the specification of 96dB will be sufficient (the IC-775DSP uses this system). When the A/D converter is in the AGC loop, the input level of the A/D converter may fluctuate significantly. For this reason, the gain control by AGC within DSP requires at least the dynamic range of the A/D converter.

Two Dynamic ranges

Dynamic range as RF performance Fig. 1

[dB] 0

Output

(a) (b)

3rdIMD

50 [dBm]

Dynamic
Dynamic range from the viewpoint of RF performance indicates to what extent the distortion component (generated due to the frequency of a signal) can be heard at the receive frequency when a frequency component different from two receive frequencies is input. Dynamic range generally means the value by 3rd order distortion component.

5. Circuit description

5-1 Digital IF filter
For IC-756PROII the transmit/receive passband width in all modes is determined by the digital IF filter using DSP. A filter of this type provides an ideal shape factor that cannot be achieved by an analog filter. If an attempt is made to increase the shape factor and band ripple characteristics of an analog filter, it is necessary to increase the number of crystal components (or ceramic elements), which may result in physical restrictions. A digital IF filter using DSP assures the desired characteristics by overlaying multiple filters. This is governed only by the processing volume of the software and it is possible to overlay such filters with any number of stages.

756PROII SSB COLINS10

When using a digital IF filter the beat frequency of an unwanted adjacent signal moves out of the filter passband width, which will not cause interference. (Fig. 1.2) This is the greatest difference between an analog IF filter and a digital IF filter. During pile-ups, such as those that occur in DXpeditions, contests, etc., it is possible to make a proper selection suitable to the application by selecting the broad filter shape (SOFT). 5-1-1 CW sharp filter The digital IF filter offers an ideal shape factor which has never been available with conventional analog filters. It enables a greater ability to receive weak stations that may lie behind radio interference. This is the filter shape that Icom would suggest to the DX hunter due to its superior cut-off performance. The cut-off performance is of a level to actually extend the CW band as explained above.

*7 Multi-rate processing A method of processing that uses the multiple sampling rates selectively, depending on the frequency of signal to be processed. Even if the processing contents are the same, the processing of a lower sampling rate will decrease the volume of calculations.
Fig. 6 Configuration of PSN type SSB modulator The two filters (filter A and filter B) shown in Fig. 6 are combined to make a 90 phase shifter. This is an all-pass filter (*6) designed using two filters in pairs so that the signal output from each filter appears to have a phase difference of exactly 90 when the same signal is input.
*6 All-pass filter: An all-pass filter is used to change only the phase without changing the amplitude of the signal sent from the all-pass filter.
Point Aphase difference Point B1
Fig. 7 Output signal of all-pass filter When a signal (frequency: f 2) having a phase difference of 90 against the signal output from the all-pass filter of two lines (A, B) transmitted from a station is modulated with the tone signal of frequency (f1) presented to the microphone, two spectra (f2f1 and f2+f1) are generated at two points, point A2 and point B2 respectively, each of whose phase relationship is as shown in Fig. 8. The signal at point A2 is added to that at point B2 as indicated. The sideband signals having a phase difference of 180 are negated while the sideband signals of the same phase add with each other, causing an output whose amplitude is doubled. The example shown in Fig. 8 shows a USB signal that is obtained. When an LSB signal is required for modulated output, it is best to add it after inverting the polarity. Since the component with a 180 phase difference is replaced with that having the same phase the modulated output appears to be an LSB signal.
All-pass filter-A a2 Demultiplexer All-pass filter-B a3 All-pass filter-A a4 All-pass filter-B

Voice input

Multiplexer
Fig. 9 Configuration of Icoms PSN type SSB modulator
For the SSB modulator shown in Fig. 9, the signal is input to each filter sequentially for each sampling cycle by using a multiplexer with 4 all-pass filters (filter A, filter B, each designed for a phase difference of 90) arranged alternately to multiply each filter output by the constants (a1 to a4). Using the multiplexer the result of multiplication is output sequentially, making it possible to gain the desired SSB-modulated output signal. For USB: Constant {a1, a2, a3, a4} = {1, 1, 1, 1} For LSB: Constant {a1, a2, a3, a4} = {1, 1, 1, 1} For PSN modulation processing using the 16-bit fixed decimal point DSP of conventional transceivers, the characteristics are adjusted to decrease the influence of the rounding error (when the filter coefficient is quantized) as it occurs. For the 32-bit floating point DSP nearly ideal characteristics are assured as the influence of errors due to quantizing is extremely limited. The IC-756PROII was re-designed with this point taken into consideration to further improve the lowband characteristics as compared with conventional transceivers. Figure 10 shows the restriction characteristics of an unwanted sideband signal and the pass characteristics of the desired sideband signal.

[dB] 20

Desired sideband

100 800

800 [Hz]
Characteristics of manual notch

[dB] 40

100 150

Unnecessary sideband

104 [Hz]

150 [Hz]

Fig. 10 SSB modulation characteristics
Characteristics of manual notch (enlarged view)

5-4 Manual notch

The IC-756PROII manual notch filter has extremely sharp characteristics which can be provided only by DSP processing. Since this manual notch is processed within the AGC loop even powerful beats are cut-off sharply without any influence upon the AGC. The filter characteristics are sharp and the passband width is held to approximately 50Hz with an attenuation level of over 70dB. This makes it possible to adjust the notch point accurately. Only the DSP provides the characteristics as shown above. With an analog type notch filter (crystal or LC notch filter) it is not possible to adjust the notch point characteristics accurately as shown above, as the frequency characteristics are liable to deviate. The manual notch assures stable filter characteristics by DSP processing because of its extremely sharp characteristics and the high-stability reference oscillator provides superior frequency stability. Accordingly it provides stable operation such that it is not necessary to re-adjust the notch point, provided the beat signal is not moved once it is set.

5-5 Speech compressor

The IC-756PROII is equipped with a newly developed RF type speech compressor. The configuration of the speech compressor is shown in Fig. 11.
Amplitude control Band limiting filter amplifier PSN modulation processing

Data buffer

Adjustment of compression gain
Analysis of amplitude level
Determination of control level
Fig. 11 Configuration of speech compressor The operating principle of this compressor is that the SSB-modulated IF signal is saved in the data buffer for a fixed time at first, and then the IF signal saved in the buffer is analyzed for amplitude level. The control level of the amplitude control amplifier is determined in accordance with the analysis, providing compression control such that the signal peak does not exceed a certain level. In other words, the amplitude of the current signal is controlled in accordance with the change in amplitude over a certain previous period.
Unlike the RF compressor used widely in conventional analog processing type transceivers little distortion will occur as the signal is not clipped. The speech compressor resembles an AGC type compressor in that the signal level is controlled, however the normal AGC method has a lot of problems. It is usually considered that the AGC type has an improved compression effect along with shortened gain recovery time constant, compared to the grip type. Setting the time constant to a low level may bring about an inferior compression effect as the adjustment range of the time constant is limited due to spoiled AGC loop stability. The Icom type compressor assures a high compression effect as there are no problems due to the non-execution of feedback processing with a proper follow-up performance against changes in amplitude of the IF signal. Even when the compression level is high only a slight distortion outside audible range may occur. To prevent the transmit passband width from extending a wide-band limiting filter is used. Since this filter was designed to prevent group delay degradation, it does not have an influence upon the modulated sound quality. Distortion generated by compressor processing For distortion generated by compressor processing, only the high order distortion may be addressed in many cases. Also, mutual modulation distortion may occur when the input signal is of 2 tones or more. The RF stage grip-processing compressor is better than the AF stage grip-processing compressor from the viewpoint of high-order distortion. The reason why it is not so highly rated from the sound quality viewpoint is because there is a problem with mutual modulation distortion. The AGC type compressor provides a lower mutual modulation distortion level as compared to the grip-processing compressor assuring better sound quality. The Icom type restricts mutual modulation distortion similarly.

ALC voltage input.

PIN No.
8V GND SEND BAND ALC TRV 13.8V

Regulated 8V output.

Output voltage Output current Same as ACC (1) pin 2. Same as ACC (1) pin 3. : 8V 0.3V : Less than 10mA
Band voltage output. (Varies with amateur band)
Output voltage Same as ACC (1) pin 8.

: 0 to 8.0V

Activates [XVERT] input/output when HIGH voltage is applied.
Input impedance Input voltage
: More than 10k : 2 to 13.8V

Same as ACC (1) pin 7.

6-2 HF/50MHz, 1kW linear amplifier
Connection to IC-PW1 (option)

To antenna

Remote control cable attached to IC-PW1 ACC cable attached to IC-PW1
REMOTE INPUT1 Coaxial cable attached to IC-PW1
ANT 2 ANT 1 GND ACC (2) REMOTE
IC-PW1 AC outlet Non Europe versions: 100120/220240V European version: 230V

Ground

IC-756PROII
6-3 Interface for digital mode
To use a personal computer to operate the digital modes (SSTV, PSK31, BAUDOT RTTY, etc.), it is necessary to install the following interface. The IC-756PROII is equipped with a digital IF filter that may narrow the receive passband range to 50Hz making it possible to select and receive only one station, even when it is used in PSK31 mode. Example of interface for digital mode (Not provided by Icom)
2k : 2k 10k 10k Pin No. Shield cable
If a filter width of 500Hz or less is selected the receive passband filter is activated to avoid interference while the transceiver receives SSBD (SSB data mode). Refer to the instruction manual or help file contained in the 3rd party software prior to use.
Connection to LINE IN or MIC IN of PC

Not connected

Shield cable

2k : 2k

10k 10k
Connection to SP OUT of PC

2SC1815 Shield cable

Connection to COM port of PC RTS GND Pin 4 of Dsub-25 Pin-7 Pin 7 of Dsub-9 Pin-5
The sections shown in squares are required only when BAUDOT RTTY is used in FSK (RTTY) mode. (Other digital mode operations are not required.)

1S1588

2SC1815
*Resistace values may be required to change, depending on computer.

code (fixed)

NG code
IC-756PROII to controller

NG message to controller

q Pre-amble synchronous code to insert the data at first. The hexadecimal FE is transmitted twice. w Reception address : The address of IC-756PROII is 64 (hexadecimal), and shows when the controller is set to E0. e Transmission address r Command : The controllable function is given by a 2-digit hexadecimal command. t Sub-command : A 2-digit hexadecimal command is used for supplementary command instructions y Data area : The area is used to set the frequency data, etc., and the length is variable, depending on the data. u Post-amble : This is a code indicating the end of a message, and is a hexadecimal FD.

Controllers

Preamble

7-3 List of commands

Command table
Command 06 Sub command Same as command 06 B0 B1 C0 C1 D0 D1 00010101*1 A1A7 Description Send frequency data Send mode data Read band edge frequencies Read operating frequency Read operating mode Set frequency data Select LSB Select USB Select AM Select CW Select RTTY Select FM Select CW-R Select RTTY-R Select VFO mode Exchange main and sub readouts Equalize main and sub readouts Turn the dualwatch OFF Turn the dualwatch ON Select main readout Select sub readout Select memory mode Select memory channel *1P1=0100, P2=0101 Memory write Memory to VFO Memory clear Scan stop Programmed/memory scan start Programmed scan start F scan start Fine programmed scan start Fine F scan start Memory scan start Select memory scan start Set F scan span (A1=5kHz, A2=10kHz, A3=20kHz, A4=50kHz, A5=100kHz, A6=500kHz, A7=1MHz) Set as non-select channel Set as select channel Set scan resume OFF Set scan resume ON Turn the split function OFF Turn the split function ON Select 10Hz (1Hz) tuning step Select 100Hz tuning step Select 1kHz tuning step Select 5kHz tuning step Select 9kHz tuning step Select 10kHz tuning step Select 12.5kHz tuning step Select 20kHz tuning step Select 25kHz tuning step Attenuator OFF Attenuator ON (6dB) Attenuator ON (12dB) Attenuator ON (18dB) Command 12 Sub command Description Select/read antenna selection (00=ANT1, 01=ANT2 : Add 0 or 1 to turn [RX ANT ] OFF or ON, respectively.) Announce with voice synthesizer (00=all data; 01=frequency and S-meter level; 02=receive mode ) [AF] level setting (0=max. CCW to 255=max. CW [RF] level setting (0=max. CCW to 255=11 oclock) [SQL] level setting (0=11 oclock to 255=max. CW [NR] level setting (0=min. to 255=max.) Inside [TWIN PBT] setting or IF shift setting (0=max. CCW, 128=center, 255=max. CW) Outside [TWIN PBT] setting (0=max. CCW, 128=center, 255=max.CW) [CW PITCH] setting (0=low pitch to 255=high pitch) [RF POWER] setting (0=mini. to 255=max.) [MIC GAIN] setting (0=mini. to 255=max.) [KEY SPEED] setting (0=slow to 255=fast) [NOTCH] setting (0=low freq. to 255=high freq.) [COMP] setting (0=mini. to 255=max.) [BK-IN DELAY] setting (0=short delay to 255=long delay) [BAL] level setting (0=max. CCW, 128=center, 255=max. CW) Read squelch condition Read S-meter level Preamp (0=OFF; 1=preamp 1; 2=preamp 2) AGC selection (1=Fast; 2=Mid; 3=Slow) Noise blanker (0=OFF; 1=ON) Noise reduction (0=OFF; 1=ON) Auto notch (0=OFF; 1=ON) Repeater tone (0=OFF; 1=ON) Tone squelch (0=OFF; 1=ON) Speech compressor (0=OFF; 1=ON) Monitor(0=OFF; 1=ON) VOX function (0=OFF; 1=ON) Break-in (0=OFF; 1=semi break-in; 2=full break-in) Manual notch (0=OFF; 1=ON) RTTY filter (0=OFF; 1=ON) Read the transceiver ID Send/read memory contents (see p. 31 for details) Send/read band stacking register contents (see p. 31 for details) Send/read memory keyer contents (see p. 31 for details) Send/read the selected filter width (0=50Hz to 40/31=3600/2700Hz)

0524 0525

0560 0561

0529 0530

Command 1A Sub command 0564 Description Send/read twin peak filter (0=OFF, 1=ON) Send/read timer functions (0=OFF, 1=ON) Send/read DSP filter type (0=SSB: sharp; CW: sharp, 1=SSB: sharp; CW: soft, 2=SSB: soft CW: sharp, 3=SSB: soft CW: soft) Send/read quick RIT/ TX clear function (0=OFF, 1=ON) Send/read SSB/CW synchronous tuning function (0=OFF, 1=ON) Send/read CW normal side set (0=LSB, 1=USB) Send/read external keypad type (0=OFF, 1=Keyer send, 2=Voice play (Tx), 3=Auto) Send/read NB level (0=0% to 255=100%) Send/read DATA mode (0=OFF, 1=ON) Send/read SSB transmit bandwidth (0=Wide, 1=Middle, 2=Narrow) Set repeater tone frequency Set tone squelch tone frequency Set the transceiver to receive or transmit condition (0=Rx; 1=Tx)
Channel code for memory keyer To send or read the desired memory keyer contents, the channel and character codes as follows are used. Channel code
Code Channel number M1 M2 M3 M4

0567 0568

Characters code
Character 09 AZ az space / ? ,. * ASCII code 3039 415A 617A 20 2F 3F 2C 2E 5E 2A Numerals Alphabetical characters Alphabetical characters Word space Symbol Symbol Symbol Symbol e.g., to send BT, enter 4254 Inserts contact number (can be used for 1 channel only) Description

07 1B 1C 00

Characters code for my call
Character 09 AZ az space . / ASCII code 3039 415A 617A 20 2D 2E 2F Numerals Alphabetical characters Alphabetical characters Word space Symbol Symbol Symbol Description
To send/read memory contents When sending or reading memory contents, additional code as follows must be added to appoint the memory channel. Additional code: 00000101 (0100=P1, 0101=P2) Band stacking register To send or read desired band stacking registers contents, combined code of the frequency band and register codes as follows are used. For example, when sending/reading the oldest contents in the 21 MHz band, the code 0703 is used. Frequency band code
Code 11 Frequency band 1.8 3.50 GENE Frequency range (unit: MHz) 11.80000011.999999 13.40000014.099999 16.90000017.499999 13.90000014.499999 17.90000018.499999 20.90000021.499999 24.40000025.099999 28.00000029.999999 50.00000054.000000 Other than above 19.90000010.499999
FM split frequency (HF/50MHz) setting The following data sequence is used when sending/reading the FM split frequency setting. q X 0 X w X 0 e X r XX

10MHz digit: 0 (fixed)

Designed for base station operation.
CT-17 CI-V LEVEL CONVERTER
UT-102 VOICE SYNTHESIZER UNIT
For remote transceiver control using a PC. You can change frequencies, operating mode, memory channels, etc.
Announces the receive frequency, mode and S-meter level in a clear, electronicallygenerated voice, in English (or Japanese).

10. Specifications

GENERAL
Frequency coverage U.S.A. Rx Tx : 0.03060.000*1 1.800 2.000*1 3.500 3.999 7.000 7.300 10.10010.150 14.00014.350 18.06818.168 21.00021.450 24.89024.990 28.00029.700 50.00054.000 0.03060.000*1 1.800 1.999 3.400 4.099*1 6.900 7.499*1 9.90010.499*1 13.90014.499*1 17.90018.499*1 20.90021.499*1 24.40025.099*1 28.00029.999*1 50.00052.000 1.810 1.850 (France) 1.830 1.850 (Italy, Spain) 3.500 3.800 7.000 7.100 10.10010.150 14.00014.350 18.06818.168 21.00021.450 24.89024.990 28.00029.700 50.20051.200 (France) 50.00051.000 (Italy) 50.00050.200 (Spain)
*1 Some freq. bands are not guaranteed.

RECEIVER

Receive system : Triple conversion superheterodyne system Intermediate frequencies : 1st 64.455MHz (for all modes) 2nd 455kHz (for all modes) 3rd 36kHz (for all modes) Sensitivity (typical) : SSB, CW, RTTY 0.16V*1 (1.8029.99MHz) 0.13V*2 (50.054.0MHz) (10dB S/N) AM (10dB S/N) 13V (0.51.799MHz) 2V*1 (1.8029.99MHz) 1V (50.054.0MHz) FM (12dB SINAD) 0.5V*1 (28.029.9MHz) 0.32V*2 (50.0MHz54.0MHz)
*1Pre-amp 1 is ON, *2Pre-amp 2 is ON Squelch sensitivity (Pre-amp: OFF):

Europe

France Italy Spain
Mode Number of memory Ch. Antenna connector Temperature range Frequency stability
: USB, LSB, CW, RTTY, AM, FM : 101 (99 regular, 2 scan edges) : SO-2392 and phono [RCA; (50)] : 10C to +50C; +14F to +122F : Less than 0.5ppm (From 1 minute after
power ON at 0C to 50C; +32F to +122F)
Frequency resolution : 1Hz Power supply requirement : 13.8V DC 15% (negative ground) Power consumption : Tx Max. power 23A Rx Standby 3.0A (typ.) Max. audio 3.3A (typ.) Dimensions : 340(W)111(H)285(D) mm; (projections not included) 1338(W)438(H)11732(D) in Weight (approx.) : 9.6kg; 21.2lb ACC 1 connector : 8-pin DIN connector ACC 2 connector : 7-pin DIN connector CI-V connector : 2-conductor 3.5 (d) mm (18) Display : 5-inch (diagonal) TFT color LCD
SSB, CW, RTTY Less than 5.6V FM Less than 1V Selectivity (representative value): SSB, RTTY More than 2.4kHz/6dB (BW: 2.4kHz) Less than 3.2kHz/40dB Less than 3.6kHz/60dB Less than 4.3kHz/80dB CW (BW: 500Hz) More than 500Hz/6dB Less than 700Hz/60dB AM (BW: 6kHz) More than 6.0kHz/6dB Less than 15.0kHz/60dB FM (BW: 15kHz) More than 12.0kHz/6dB Less than 20.0kHz/60dB Spurious and image : More than 70dB rejection ratio (except IF through on 50MHz band) AF output power : More than 2.0W at 10% distortion (at 13.8V DC) with an 8 load RIT variable range : 9.999kHz PHONES connector : 2-pin connector 6.35 (d) mm (14) EXT SP connector : 2-pin connector 3.5 (d) mm (14)/8

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Certificate Number Q14190
Icom Inc. (Japan), is an ISO9001 certification acquired company.

03HK0080 @2003 Icom Inc.

Printed in Japan