Tascam CG-1800

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 Tascam CG-1800 is designed for small to large-scale video/audio synchronization systems.

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.

High-precision synchronization systems can be created

Internal clock uses a high-precision OCXO that is not influenced by the temperature of the environment

The crystal oscillator is the heart of the clock generator. In 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 (factory default value), which exceeds that of a TCXO (temperature-compensated crystal oscillator), this unit is key in the creation of high-precision synchronization systems – with word output frequency stability of ±0.005 ppm or less per day.

Input connector that supports 10 MHz signal – allowing the creation of systems with even higher precision

An input connector that supports an external 10 MHz signal enables the CG series to be connected to a rubidium clock or GPS clock for even higher precision.

Designed for high reliability and dependable stability

Power supply redundancy with two power supply circuits

With two power supply circuits, the CG-1800 features redundancy to prevent mishaps caused by power outages.

Redundant video reference/word clock input

With two inputs each for video reference (for CG-200 and CG-1800) and world clock signals, there is redundancy to prevent problems due to external clock interruption.

Jitter management circuit provides stable clock

External clock jitter is reduced using an original TASCAM circuit design that incorporates a high-performance video clock generator device, featuring an FPGA (Field Programmable Gate Array) 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, improving system stability.

Glitch-free relocking circuit prevents noise and skipping during clock dropouts and recovery

The CG series constantly measures the external reference clock. In devices that do not have built-in countermeasures, and the master clock signal drops out, the video reference and word clock signals could become out of phase, and sound might skip during the dropout – and again during recovery. In each CG model, if the clock drops out, a substitute reference clock signal is maintained with a high-performance holdover. During this time, the video reference and word clock signals are kept in-phase, so restoration of synchronization to the reference signal can occur without glitches, preventing video/audio noise and skipping sounds when recovering from a dropout.

Abundant input and output connectors

Numerous output connectors, including 12 word clock outputs

In addition to twelve word clock outputs and four video outputs (for CG-2000 and CG-1800), the digital outputs include two AES3/AES11 and two S/PDIF outputs, making this unit 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 - enabling them to be used in systems with ProTools and other DAW software.

A variety of video signal formats supported (for CG-2000 and CG-1800)

Analog NTSC/PAL and digital HD Tri-level video signal formats are supported.

Support for maintenance and identification of issues if problems occur

Analyzer function that can measure output device termination

In the installation of broadcasting and large-scale post-production studios, numerous connected devices and complicated wiring are common. The CG-1800 has an analyzer function that allows it to measure phase difference, input frequencies, input levels and the terminations of output devices - enabling it to provide support when troubleshooting problems should they occur.

Optimal levels can be provided to other devices by adjusting wordclock output

Depending on the routing of wiring and the receiving devices, signal levels could be reduced – resulting in proper reception failures. Since the output of the CG series can be set to multiple levels, it can provide optimal signal levels to connected devices.

Checking conditions if problems occur is possible through logging and GPO parallel output

One function that enables identification of the causes of trouble is the logging function. In addition to being able to check the log on the CG-1800 display, you can also capture the log as a CSV-format file on a USB flash drive. Moreover, you can also monitor the conditions of trouble occurrence by using GPO parallel output.

Self-calibration function enables maintenance by users

Since crystal oscillators change over time, regular calibration is necessary. In order to avoid problems that could lead to broadcast trouble, timely inspections and regular maintenance are required. The CG-1800 has a self-correction function, enabling users to conduct maintenance using external signal input* and simple operations. (*Use of the self-calibration function requires preparation of a separate PPS-output 10MHz oscillator with a built-in GPS antenna.)

Designed for durability

Durable nut-coupling Amphenol BNC connectors

Since the Amphenol BNC connectors use nuts for coupling, they are extremely resistant to pulling, twisting and multiple connect-disconnect cycles.

Independent circuit boards

Each connector has an independent circuit board. This provides excellent resistance to the twisting and pulling of cables and suppresses interference between connectors.

Features at a glance

• A series of highly reliable, highly stable and highly accurate master clock generators
• CG-1800 for small to large postproduction studios
  • Stable synchronization between picture and sound
  • Flexible system setup with a large variety of audio and video formats (Audio: Wordclock, AUS3, AES11, SPDIF, Video: NTSC, PAL, HD tri-level)
  • High-quality OCXO (Oven Controlled Crystal Oscillator) oscillator for highly accurate clock signal generation
  • Jitter management circuit and glitch-less relock management to avoid problems caused by master clock signal
  • Clock input supports clock rates up to 10 MHz
  • 4 video sync outputs, 12 wordclock outputs, 2 AES3 or AES11 outputs, 2 SPDIF outputs
  • 2 wordclock outputs support Fs/4, Fs/2, 2 Fs, 4 Fs and 256 Fs to be used with ProTools and other DAW software
  • Support for 0.1%, 4 % pull-up/pull-down
  • Self-calibration function* allows maintenance by operator for optimum accuracy at any time
  • Output levels of the wordclock connectors can be adjusted
  • Analyzer feature allows to measure input frequencies, input levels and the termination of output devices
  • Logging function for troubleshooting (check the log on the display or capture a CSV-format file on a USB flash drive)
  • Up to 4 system settings can be saved for recall and saved settings can be imported and exported via USB
  • Panel-lock to prevent misoperation
  • Organic EL display with a wide viewing angle
  • Firmware updates possible using the USB port

*Use of the self-calibration function requires preparation of a separate PPS-output or 10-MHz oscillator with a built-in GPS antenna

Specifications

Design and specifications subject to change without notice.