Error compensation for sigma-delta modulated digital signals or the like

A noise control system for use on a transmission path for a digital signal constituted of primary data in which each sample of an analog signal is expressed by one bit of information, and of error correction data for use in correction of error in the primary data, the noise control system comprising:

• (a) an error-detecting and -correcting circuit for detecting and, if possible, correcting errors in the primary data of the digital signal with use of the error correction data, the error-detecting and -correcting circuit having a first output for delivery of the digital signal, and a second output for production of an uncorrectable error signal indicative of the presence or absence of an uncorrectable or uncorrected error in or from the digital signal;
• (b) an interpolation data generator for generating a predefined interpolation datum for insertion in each uncorrectable or uncorrected error location in the digital signal, the interpolation datum being constituted of a plurality of binary 0s and a plurality of binary 1s, the 0s and 1s in each interpolation datum being equal in number and being so arranged as to represent a frequency in excess of an audible range of frequencies;
• and
• (c) an interpolation circuit connected to both the error-detecting and -correcting circuit and the interpolation data generator for inserting, when the uncorrectable error signal from the second output of the error-detecting and -correcting circuit indicates the presence of an uncorrectable or uncorrected error, the predefined interpolation datum in the location of the uncorrectable or uncorrected error in the digital signal issuing from the first output of the error-detecting and -correcting circuit.