Analog Devices unveils triple video delay line IC

Analog Devices has introduced a low-power, triple-skew-compensating video delay line IC for transmitting sharp images long distances over twisted-pair cable.

The company claims that the AD8120 triple video delay line IC consumes 50 per cent less than its closest competitors; while all three channels at maximum delay and 0.8 per cent channel-to-channel gain matching delivers accurate RGB colour video.

The AD8120's 150MHz bandwidth along with its 50ns total delay provides a 7,500MHz-ns BWxD (bandwidth x delay benchmark).

The BWxD is an industry benchmark that allows designers and manufacturers to accurately compare performance specifications of triple video delay line ICs.

The AD8120 compensates for the skew created by Cat5, Cat6 or Cat7 cables when transmitting analogue video over long distance cables.

Skew, or arrival time mismatch, between video signals occurs during video transmission in unshielded twisted-pair cables due to the different twist rates that are used for each pair.

For this reason, some pairs are longer than others, and in long cables the difference in propagation time between two pairs can be well into the tens of nanoseconds, creating a noticeable degradation in video performance.

To solve this problem, the AD8120 contains three delay paths that provide broadband delays up to 50ns in 0.8ns increments using 64 digital control steps or analogue control adjustment.

The delay technique used in the AD8120 minimises noise and offset at the outputs making the AD8120 suitable for applications that receive high-resolution video over UTP (unshielded twisted pair) cables.

The AD8120 provides individual delay controls for each channel.

The delay times are set independently using a standard four-wire SPI bus or a standard I2C bus, or by applying analogue control voltages to the VCR (voltage control red), VCG (voltage control green) and VCB (voltage control blue) pins.

Analogue control offers a solution for systems that do not have digital control available.

The AD8120 is designed for use with ADI's AD8123 triple UTP equaliser in video over UTP applications, and it can also be used in other applications where similar controllable broadband delays are required.

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