Chapter 12: Randomization Methods for Telemetry Systems
Abstract
A randomizer is a device that manipulates the source data stream before transmission by applying a pseudo-random binary sequence; this provides maximum bit transition density. A de-randomizer reverses these manipulations at the destination. This chapter specifies bit-level randomization methods that improve the spectral qualities, demodulation, and decoding of telemetry signals. Maximum bit transition density is needed to maintain the spectral qualities of IRIG 106 modulations, aid in telemetry signal acquisition, and maintain bit (or symbol) synchronization of a received telemetry signal. The randomizer prevents degenerative data patterns from degrading data quality. The following randomization and de-randomization methods are recommended for wireless serial streaming telemetry data links. Randomization/de-randomization is defined in multiple chapters of this standard. This chapter consolidates those definitions into one place. There are two types of randomizers used in serial-streaming links: a self-synchronizing randomizer known as the IRIG randomizer; and a non-self-synchronizing randomizer known as the CCSDS randomizer. The choice of randomizer depends on the application.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 11, 2023
- Accession Number
- AD1205422