Receiver for independent sideband signals

摘要

A receiver for independent sideband (ISB) signals comprises means (30 to 54) for producing digitised quadrature related zero IF versions of the received signal which are applied to a complex FIR filter structure (56) comprising respective real low pass filters in which alternate coefficients (C1 to CN-1, C0 to CN) are non-zero. The FIR filter structure is illustrated in greater detail in Figure 3 (not shown). The respective upper and lower sidebands (USB, LSB) are recovered by obtaining the sum and difference of the outputs of the respective filters. The respective sideband signals (USB, LSB) are stored in RAM (58) and when it is desired to reproduce the stored signal it is expanded, equalised and converted to an analogue signal which is supplied to an audio transducer (64).