Circuit analyzes RZ pulse trains

Pulse trains coded in any one of a variety of formats are frequently used to transmit telemetry data or other coded information. Equipment is needed for both coding and decoding functions to code the data and to decode or analyze the data. Many versatile pieces of equipment exist for analyzing pulse train data. However, in cases where only one type of data exists, in this case RZ data, the circuit presented can do the job with minimal parts count. This circuit was used to simplify design, and make easy construction checkout and troubleshooting. The main feature is that the circuit can lock on to data that are available on one line only. It will synchronize to the data without having a line present that transmits the clock pulses of the original data source. In this example, the frequency of the data source was known to be 200 KHZ and the incoming data had been preconditioned to a 5-V TTL signal.