Signal Channel Output Filters - Ametek 7230 Instruction Manual

AQN Auto-Phase (auto quadrature null)
The instrument adjusts the reference phase to maximize the X channel output and
minimize the Y channel output signals.
FRQ[.] Reference frequency meter
If the lock-in amplifier is in the external reference source modes, the FRQ command
causes the lock-in amplifier to respond with 0 if the reference channel is unlocked, or
with the reference input frequency if it is locked.
If the lock-in amplifier is in the internal reference source mode, it responds with the
frequency of the internal oscillator.
In dual reference mode it reports the frequency of the reference 1 channel.
In fixed point mode the frequency is in mHz, and in floating point mode the
frequency is in Hz.
FRQ1[.] Reference frequency meter, reference 1 channel
In dual reference modes, the FRQ1 command causes the lock-in amplifier to respond
with 0 if the reference 1 channel is unlocked, or with the reference input frequency if
it is locked.
In fixed point mode the frequency is in mHz, and in floating point mode the
frequency is in Hz.
FRQ2[.] Reference frequency meter, reference 2 channel
In dual reference modes, the FRQ2 command causes the lock-in amplifier to respond
with 0 if the reference 2 channel is unlocked, or with the reference input frequency if
it is locked.
In fixed point mode the frequency is in mHz, and in floating point mode the
frequency is in Hz.
LOCK System lock control
Updates all frequency-dependent gain and phase correction parameters.
VRLOCK [n] Virtual reference mode lock
The Seek option of the frequency sweep mode must be used before issuing this
command, for which the value of n has the following significance:
n Mode
0 Disables virtual reference mode
1 Enters virtual reference mode by enabling tracking of the signal frequency

6.7.03 Signal Channel Output Filters

NOISEMODE [n] Noise Measurement Mode control
The value of n sets the noise measurement mode according to the following table:
n Function
0 Noise measurement mode off
1 Noise measurement mode on.
When the noise measurement mode is turned on, the output filter time constant is
automatically adjusted until it lies in the range 500 µs to 10 ms inclusive, the
Chapter 6, COMPUTER OPERATION
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