Tx/Rx pair converts analogue to HD video over existing coax

June 24, 2014 // By Graham Prophet
Intersil's HD-SDI transmitter and receiver support upgrading from analogue to HD Video while using previous-generation coax cabling. The TW6872 Triple-rate SDI Transmitter and TW6874 Quad Receiver lower system costs and extend reach for video applications.

TW6872 HD-SDI video transmitter and TW6874 quad HD-SDI receiver use Dirac VC-2 mezzanine compression, an end-to-end solution enabling latency free video over extended cable distances. The new devices are designed to conform to the SMPTE standards for SD, HD and 3G serial digital transmission and offer a high level of integration to enable reduced system costs for video surveillance cameras, industrial cameras, digital video recorders (DVRs) and video mixers and switches.

HD-SDI usage in the security and industrial markets has been limited by cable reach and the high cost of cabling infrastructure. The TW6872 triple-rate HD-SDI video transmitter and TW6874 quad HD-SDI video receiver deliver HD quality without requiring expensive cabling upgrades. Offering robust operation in real-world installations, the TW6872/4 devices use SMPTE VC-2 based Dirac compression to enable HD video transmission at SD-SDI cable distances of 300+ metres.

The TW6872 transmitter with low-jitter clocking (0.09 UIpp) and an integrated cable driver with pre-emphasis enhances output signal transitions to achieve superior cable reach. The TW6874 receiver with an adaptive equaliser compensates for frequency-dependent cable attenuation, delivering longer cable reach in combination with the TW6872 or other HD-SDI transmitters.

The high level of integration in both the TW6872 and TW6874 devices reduces development and manufacturing costs for camera makers so that HD cameras are more cost effective to bring to market. The TW6872 video transmitter integrates both an analogue and digital audio input, eliminating the need for an external ADC. An integrated cable driver contributes to extending cable distance and eliminates the need for external components for compensation. An internal PRBS test pattern generator replaces expensive test equipment typically needed during camera manufacturing and installation. Video enhancement features in the TW6874 receiver enable auto adjustment of brightness, colour, contrast and saturation at the DVR.

The TW6872 HD-SDI video transmitter in a LQFN76 (9 x 9mm) package costs $7.00 (1,000). An evaluation platform, the TW6872-NA1-CR-EVALZ, is $995. The TW6874 transmitter will cost