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Appendix A: Optical versus electrical digital audio output
The electrical connection has more bandwidth, typically more than 50MHz, and this
will maintain the pulse quality at the receiver end, which reduces jitter.
However there is noise emission from the digital pulses, which can potentially disturb
the video signal or TV/FM receiver. A short cable, e.g. less than 75cm and not
crossing the video cables or antenna cables, is necessary. Also, disturbances
through the receiver’s ground plane can occur, which can add new jitter.
The optical transmitter in DVA100, DVA120, DVA150B and DVA250B has a high
bandwidth of 14MHz, and ensures that the signal quality is maintained, even at a
transmission rate of 96 kHz.
The optical connection is completely free from ground return current and noise
emission. This will in many cases more than justify the use of an optical connection in
a complicated audio/video system.
If you face any noise problems, e.g. humming noises or noise caused by an electrical
connection, then change to an optical connection.
