25-Seven Systems program delay manager, Руководство оператора

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52 25-Seven Program Delay Manager Version 2.3 Manual April 2013
Under extreme circumstances, an intermittent digital input can cause erratic audio be-
havior. If this happens, power-cycle the PDM.
Digital Output
When set to AES/EBU via the
Audio
menu, this output conforms to IEC 958 Profes-
sional (5v p-p, 110 balanced) on XLR connectors. Output is 16-bit PCM linear.
When set to s/pdif, the voltage and impedance switches to IEC 958 Consumer (.5v p-p,
75
unbalanced): connect signal to pin 2 and shield to pin 3 only. Do not connect pin 1
for s/pdif operation.
This digital output is always active on XLR-equipped PDMs, so you can use PDM as
the converter if you have to handle an analog signal in a digital plant.
If there is no signal on the digital input jack, PDM provides its own low-jitter clock at a
44.1 kHz sample rate. When there is a valid 44.1 or 48 kHz signal at the digital input
jack—even if analog inputs are selected—the internal clock and digital output are
locked to it. Use this feature to make sure PDM’s output works smoothly with your
routers and other equipment. But see the warning about digital clocking above.
Analog Inputs
Information about input and output levels is on page 20. Unbalanced operation
is not recommended.
These are electronically balanced XLR female, pin 2 hot, with a load of 20k : this makes
them compatible with all modern electronically-balanced outputs. If fed from a trans-
former-balanced output, we recommend bridging a 680
resistor between pins 2 and 3.
Analog Outputs
These are electronically balanced XLR male, pin 2 hot, designed to feed a load of 600
or greater.
PDM uses advanced algorithms to process signals in true stereo, with no smearing or
variation in the stereo field during time compression. So while the analog outputs (and
analog inputs) are labeled
CH1
and
CH2
on the back panel, we assume you’ll be using
them for the left and right channels of a stereo pair and that’s how we’ve written this
documentation.
However, you can also use PDM for dual, identical processing of two mono signals.
There’s no cross-talk.
Bypass Relays
Analog and digital XLR inputs and outputs are wired to bypass relays. In the event of a
power failure, incoming audio is connected directly to the outputs. PDM powers up in
bypass.