The CG Series master clock generators are based on a high-precision crystal oscillator with jitter management and glitch-free relocking for ultra-high clock precision. The CG-2000 is designed for the needs of broadcasting and post production, the CG-1800 for small to large-scale video/audio synchronization systems, and the CG-1000 for recording studios, live sound applications and professional musicians.
The crystal oscillator is the heart of the clock generator. In each model of the CG Series, an OCXO (oven-controlled crystal oscillator) is used for its high precision, and the fact it is not influenced by the temperature of the environment. Boasting a clock frequency precision of 0.01 ppm*1, which exceeds that of a TCXO (temperature-compensated crystal oscillator), these units are key in the creation of high-precision synchronization systems with word output frequency stability of ±0.005 ppm or less per day. Each model is equipped with an input connector that supports a 10-MHz signal. This allows it to be connected to a rubidium clock or GPS clock for even higher precision.
External clock jitter is reduced using an original Tascam circuit design that incorporates a high-performance video clock generator engineered with a FPGA*2 and a PLL (phase-locked loop) circuit with a discrete filter. This enables a stable clock signal to be provided to the video/word outputs for improved system stability. The glitch-free relock circuit prevents noise and skipping sounds caused by master clock dropouts.
In addition to twelve word clock outputs and four video outputs (CG-2000 and CG-1800 only), the digital outputs include two AES3/AES11 and two S/PDIF outputs, making the units useful for large-scale audio/video synchronization systems, and a wide variety of other applications. Of the twelve word outputs, two also support x2Fs, x4Fs and 256Fs output for use in systems with ProTools and other DAW software.
The CG Series has multiple functions to support maintenance, and the identification of issues if problems occur. The analyzer function measures output device termination, input level measurement (both for CG-2000 and CG-1800 only), and the measurement of input frequencies. These built-in features enable the devices to provide troubleshooting support. Additionally, a logging function allows issues to be listed, and saved to a CSV file format on a USB flash drive. Since crystal oscillators change over time, regular calibration is necessary. In order to avoid possible sync problems, timely inspections along with regular maintenance is required. For this purpose, the CG Series has a self-calibration function, enabling users to conduct maintenance using an external input signal*3 and simple operations.
Amphenol BNC connectors on the chassis use nuts for coupling, making them very durable. Also, a single circuit board is used for each connector providing excellent resistance to the twisting and pulling of cables, and the suppression of interference between connectors.
The CG Series is the latest in the line of innovative Tascam professional digital products – engineered with the latest digital clocking technology.
*1 Factory default value
*2 FPGA (Field Programmable Gate Array)
*3 Use of the self-calibration function requires preparation of a separate PPS-output 10MHz oscillator with a built-in GPS antenna.