A crystal controlled reference and master clock generator. A powerful building block, used when asynchronous digital output modules installed in the GPU frame has to be synchronized by the GPU bus. It synchronizes all digital outputs by means of an internal crystal oscillator, able to phase lock to an external PAL Video, Word or an AES digital audio signal.
Besides controlling the modules via the GPU bus, two 75 Ohms Word outputs and two 110 Ohms RS422 transformer balanced AES outputs are available on the back panel. 44.1 kHz, 48 kHz or 96 kHz sampling frequency is selected by the pushbutton on the front.
It locks the AES Z-preamble (at 48 and 96 kHz) or the AES X-preamble (at 44.1 kHz) to the video frame start, as prescribed in the AES recommendations.
The design is based on an extensive sync safety philosophy, featuring a unique glide principle and an internal flywheel, guarding efficiently against sync drop outs. The phase locked loop exhibits an excellent Jitter Rejection Ratio, and is able to clean up and stabilize a jittery house sync. The reference is automatically selected by priority: 1. Video, 2. Word, 3. AES, 4. Internal crystal.
