RA-4000 Time Code Generator

The following description of the RA-4000 Time Code is from the Sixth Edition of the NAB Engineering Handbook.

  "The code frame format is made up of a thirteen-bit synchronizing section together with a 65-bit addressable group. The synchronizing section performs three basic functions: a burst of uninterrupted clock transitions to enable the decoder to lock to the bit clock, a repetitive pattern to enable an address synchronizing pulse to be derived, and tape transportation direction to be defined by examination of the direction of predetermined transition. The addressable group is divided into blocks of five, with the fourth data bit repeated to form the fifth bit. This reduces the effective data bits to four per block (or fifty-two in all). This insertion of two adjacent identical bits in each block of five addressable bits preserves the capability of defining address sync and tape direction. One-half of the available data bits per frame are used to form the consecutive time code, while the other half is available for identifying data that can be maintained over successive edits and generations."

 
Back to RA-4000