A real-time digital frequency transposer for the 100 Hz to 1 25 MHz band

A real-time digital signal processor is described which, because of its wide band operation, close tolerance bandwidths and linear phase/frequency response, has a wide range of applications. These include general data handling and conditioning, frequency shifting and transposition, pre-processing for spectrum analysers and bandwidth compression. Apart from analogue-digital convenors and preamplifiers, the instrument is wholly digital and makes use of a combination of microprocessor techniques and hardwired logic to achieve performance goals. The transposer can either be operated manually or directly from a host digital computer via a parallel interface. Spare card space is also available to include either an IEEE488 or RS232 interface, as required.