Digital audio delay chip synchronizes audio and video
Texas Instruments’ TPA5050 digital audio delay with IIC control is designed for high definition and flat panel TV applications. The device provides cost-effective synchronization of audio and video in a single integrated package that conserves board space and simplifies channel configuration.
Audio/video (A/V) synchronization issues arise because video processing is more intensive than audio processing. As a result, audio is ready for playback before the video. Without synchronization, what viewers hear will not match what they see on the screen -- where the timing of lips moving is off from the words being heard, for example -- significantly impacting the overall viewing experience.
Also known as "lip sync," A/V synchronization is maintained by delaying playback of the audio stream, until the video stream has finished processing. The actual delay required for synchronization depends upon the type of A/V signals and the current video mode.
Synchronization also plays a role in wireless multi-channel speaker applications. Given the inherent processing delays of wireless transmission, it takes more time for transmitted channels than non-transmitted channels to output audio. The non-transmitted channels, therefore, must have additional delay to synchronize them with the transmitted channels.
Because the new chip can provide up to 170 ms of delay per channel--and with resolution down to a single sample--the TPA5050 digital audio delay can make the audio and video delay imperceptible. With 170 ms of delay per channel, the TPA5050 digital audio delay can synchronize the most demanding TV applications.
In addition to minimizing cost, board space and configuration complexity, the TPA5050 digital audio delay will automatically clear the delay memory during a delay time change, eliminating undesirable pops and clicks. The TPA5050 digital audio delay supports 16 bit to 24 bit data, sample rates from 32 kHz to 192 kHz, and all standard audio configuration interfaces, including I2S, Left- and Right-Justified.
All internal clocking on the TPA5050 digital audio delay is generated from the bit clock so no crystal or oscillator is needed. The inputs are 5 V tolerant so interfacing with a host of microcontrollers and audio processors is not an issue. Developers requiring longer delays for professional or specialized applications can cascade multiple TPA5050 chips.
The TPA5050 is housed in a 4 mm x 4 mm QFN package. Two other members of the TPA505x family, the TPA5051 and the TPA5052 are currently sampling. Available now in production volumes, the TPA5050 digital audio delay costs $3.20 each in 1000-unit quantities.
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