INT-9415 PCM Symbol Stream Generator

Overview

The INT-9415 produces an I/Q symbol stream that is used in testing PCM processing systems and their components. A symbol stream is the product of the various level PCM encoding formats and the radio level format in use. Since these vary widely, the design of PCM processing systems must be very flexible. Test and functional verification systems for these systems must have equal flexibility as well. To provide this flexibility the INT-9415 symbol streams are software defined. Using software hosted on an IBM/PC or the INT-9415 itself, symbol stream files of up to ITU / CEPT level 5 multiplex may be created with or without radio level coding. Symbol streams are stored as disc files within the INT-9415 unit. This permits a large library of symbol stream files, each with a different PCM and/or radio format, to be readily available for use. Upon operator command a symbol stream file is loaded into the arbitrary symbol pattern generator and then is output continuously, restarting at the beginning of the file when the end has been reached. The INT-9415 then applies constellation mapping to the symbol stream from the pattern generator, and outputs the mapped symbols to the front and rear panels of the unit. This software-based approach allows the INT-9415 to create symbol streams to match virtually any PCM multiplex level and radio level format. Also new symbol files may be acquired using a wideband tape recorder, stored on INT-9415 disc and recalled for playback.