Multifunction audio digitizer

Claim 1

Apparatus for encoding data waveforms for modulating data transmission apparatus comprising: a. transducer means for deriving an analog voltage signal representative of the input signal; b. controlled analog amplifier means for amplifying said representative analog voltage signal; c. analog adder means for algebraically adding said representative analog voltage signal to a second analog voltage signal which is derived by feedback means, thereby forming a composite signal potentiometer for manually controlling the input bias of said adder means; d. window comparator means, having a comparison window whose width is preset to the analog equivalent of one binary step, for detecting the magnitude of said composite signal and for generating a ''''count-up'''' signal at a first output terminal of said comparator means when said composite signal exceeds a preset negative threshold, and a ''''count-down'''' signal at a second output terminal of said comparator means when said composite signal exceeds a preset positive threshold, thereby tending to maintain said composite signal at zero; e. timing pulse generator means for generating timing pulses for timing the system; f. a pair of control gates for receiving, as first inputs, the respective ''''count-up'''' or ''''count-down'''' signals from said comparator means; for receiving, as second inputs, said timing pulses; and for producing delta modulation output signals only when said first input is present and is in coincidence with said timing pulse; output means for extracting said delta modulation signals; g. digital up-down counter means for receiving and counting said delta modulation output signals in either a count-up or countdown direction, thereby producing pulse-code-modulation signals at the output of said counter means which equal the analog input signal when both of said control gates have no output output means for extracting said pulse code modulation signals; a peak modulation monitor for monitoring the carry line of the said counter means; h. means responsive to said control gates for supplying said delta output modulation signals to only one at a time of said counter means inputs, thereby producing a delTa modulation signal with a count-up, count-down, or no-count format; and i. digital-to-analog converter means for monitoring the output of said counter means and for generating an analog feedback signal for application as said second analog voltage signal to said analog adder means.