Commonwealth Scientific and Industrial Research Organisation

David Andrew Abbott

Joseph Abraham Pathikulangara

Valeriy Dyadyuk

John David Bunton

Boyd McGregor Murray

Boyd Mcgregor Murray

John Bunton

A circuit for transmission and reception of multi-channel communications is disclosed. The transmitter path includes a digital modulation circuit receiving multiple channel binary data, and for each channel generating a digital representation of the data. A digital-to-analogue (D/A) conversion circuit (-) is provided for each data channel. Each D/A conversion circuit receives and converts respective channel digital representations to produce a resultant band limited analogue signal (-). The band limitation arises due to a characteristic of said channel digital representations. A bandpass filter (-) receives and filters each analogue channel signal. The band width to the start of the stop band of each bandpass filter is wider than a respective band limited analogue channel signal and wider than the Nyquist bandwidth arising from the sampling rate of said D/A conversion circuit. In this way, signal power in unwanted Nyquist zones is effectively removed. A frequency translation circuit (-) abuts the multiple channel bandpass filtered analogue signals in the frequency domain without any guard bands between adjacent channel signals.

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Abbotsford, Australia

David Andrew Abbott