Hardware
expansion
The PGF8
top-box: 8
programmable
filter channels
The PGF8 is designed for researchers in vibration analysis and
other systems generating periodic signals. It provides eight
signal-processing channels plus auxiliary circuits. The heart of
each channel is the switched-capacitor filter (SCF) and
selectable gain, but there are also options for AC coupling, and
simultaneous sample-and-hold (S&H). The channels have
individual control of gain level, and individual enabling of the
SCF and the AC coupling. The SCF pass-frequency and the
S&H functions are applied equally to all channels. The channel
outputs are multiplexed and connected directly to the
motherboard ADC via an internal coaxial cable.
Auxiliary circuits include
Trigger A
and
Trigger B
inputs with
programmable thresholds; a phase-locked loop (PLL); and a
programmable frequency multiplication of the Trigger A
frequency. The latter two functions are useful when triggering
information comes from smoothly-varying systems such as
rotating shafts.
The PGF8 generates three digital outputs,
Event Outputs 0
and
1
, and
Trig Out
, on BNCs handily positioned directly above the
corresponding inputs on the Power1401. Front-panel access is
provided for motherboard DACs 2 and 3. The frequency-
multiplier analogue control voltage is brought out to a front-
panel BNC labelled
Speed
.
The PGF8 top-box is driven by internal connections to the
Power1401 motherboard. This expansion board, the
CED 2701-21, requires the Power1401 expanded mechanics
(can and case), and it is usually more convenient to send an
unexpanded unit back to CED for upgrading than for the end-
user to install it.
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Summary of Contents for Power1401-3
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