Offset dither digital generator - has counter incremented for each repetition of analogue signal to be digitised, with counter output connected to D=A converter

摘要

The digital dither generator produces a sequence of dither voltages to be combined with an analog input signal before it is digitised by an m-bit quantiser, the dither generator comprising a clock pulse generator for producing a pulse at a repetition rate equal to that of the analog input signal. There is an n-bit unit for converting a digital signal to an analog dither value and an n-bit unit for counting the clock pulses, the outputs of the counter being coupled to the control inputs of the digital-to-analog converter. There is a summer for combining the analog input signal with the analog dither value, the output being coupled to the input of the m-bit quantiser.