Edinburgh, UK Wolfson Microelectronics released the WM8804 and WM8805 audio transceivers which address the challenges of cost-effective S/PDIF audio data transfer in LCD televisions, hi-fi and PC motherboards.
Integral to the transceiver's design is a PLL with an intrinsic jitter period of 50 ps and jitter rejection frequency of 100 Hz. The WM8804 and WM8805 contribute a negligible level of jitter to the audio system. Traditionally, S/PDIF transceivers can only suppress jitter above 10 kHz and have no effect on the low and medium frequencies, which have the greatest impact on audio quality. The WM8804 and WM8805 are capable of suppressing jitter on the audio signal at frequencies above 100 Hz, removing any unwanted distortion or problems. The PLL design enables the WM8804 and WM8805 receivers to lock onto and recover the data and timing from poor quality input signals, thereby allowing the transceivers to accept S/PDIF signals from any source, even if the input signal is severely degraded.
A further benefit of the PLL is the reduction in component count for the overall system. The PLL can be used to synthesize crystal-derived clock signals and, without an external filter, can operate as a master timing source for the audio system. The WM8804 and WM8805 are fully compliant to the IEC60958-3 standard for S/PDIF, including a unique “with flags” mode. Status and error information can be extracted using a variety of methods.
The WM8804 has one input and one output for use in LCD TVs, DVD recorders, musical instruments and other personal electronics requiring high-performance digital audio. The WM8805, with eight inputs and one output, is specifically designed for use in systems where digital audio channel switching is necessary, including AV and DVD receivers and professional and home recording systems.
Wolfson Microelectronics, 440-0-131-272-7000, www.wolfsonmicro.com