Digital video communication system having a network clock source

摘要

In a digital video communication system, a network clock source is provided to supply a common clock pulse synchronized with the transmission speed of the system to each station through a transmission channel to allow it to derive a video sync pulse. This sync pulse is applied to a video signal source to generate an analog composite television signal. A quantization sampling pulse is derived from the video sync pulse which is contained in the composite television signal to quantize the composite television signal. The quantized video signal is stored in a buffer and forwarded to a receiver station in response to the received network clock pulse, so that the quantization sampling rate and the transmission sampling rate of a transmitter station of the system are synchronized with each other. The sampling rate of the dequantization process at the receiver station is also synchronized with the transmission sampling rate.