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WJ-9546 FDM demodulator

Top Inside Receiver card DSP card Audio reconstruction card
WJ-9548 data sheet (same design with front panel controls)

WJ-9546 Frequency Division Multiplex demodulator

This is basically a 6 channel HF receiver for 0-20 MHz LSB, USB. It was originally designed for monitoring any six (12 or 24 optional) satellite or microwave telephone conversations in the days when the calls were relayed as SSB signals multiplexed up into groups and supergroups.

The WJ-9548 is the same unit with front panel controls. Either unit can be used as six simultaneous shortwave radios if all you want to do is monitor SSB. A WJ engineer told me they set one of these up at a trade show to monitor shortwave and came back wit the idea of developing a DSP radio, which became the WJ-8711.

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WJ-9546 inside

Beautifully engineered. The six receiver cards are bottom center. There is a lot of sophisticated hardware in this little box. Internally this FDM unit looks similar to the inside of the WJ-8691.

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This is one of the six receiver cards.

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This is the DSP card. The DSP is a Motorola XSP5601ZL120.

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This is the card labeled "AUDIO RECON" for audio reconstruction. It is a DSP demodulator for the six audio channels. The DSP is another Motorola XSP5601ZL120.

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