Telemetry Standards, RCC Standard 106-20, Chapter 5: Digitized Audio Telemetry Standard
Abstract
This chapter defines continuously variable slope delta (CVSD) modulation as the standard for digitizing audio and addresses the method of inserting CVSD encoded audio into a pulse code modulation (PCM) stream. Additional information and recommendations are provided in Appendix 5-A, which was extracted from the applicable sections of Military Standard 188-113, which has been canceled with no replacement. Additional information regarding the insertion of the digitized voice signal into a PCM frame may be obtained in the documentation of US Patent 5,557,635. For the purpose of this standard, the following definitions apply. Band-Limited Audio: An audio signal (typically consisting of voice, tones, and sounds) that is limited to a subset of the audio spectrum. For most aircraft audio applications, the spectrum between 100 and 2300 hertz (Hz) is adequate. Continuously Variable Slope Delta Modulation: The CVSD modulation is a method of digitizing a band-limited audio signal. The CVSD modulator is, in essence, a 1-bit analog-to-digital converter. The output of this 1-bit encoder is a serial bit stream, where each bit represents an incremental increase or decrease in signal amplitude and is determined as a function of recent sample history. This standard applies to audio signals only.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2020
- Accession Number
- AD1103899