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LR[.]
Log Ratio output
In integer mode, the LR command reports a number equivalent to
1000×log(X/ADC1) where X is the value that would be returned by the X command
and ADC1 is the value that would be returned by the ADC1 command. The response
range is -3000 to +2079
In floating point mode, the LR. command reports a number equivalent to
log(X/ADC1). The response range is -3.000 to +2.079
NHZ.
Causes the lock-in amplifier to respond with the square root of the noise spectral
density measured at the Y channel output, expressed in volt/Hz or amps/Hz
referred to the input. This measurement assumes that the Y channel output is
Gaussian with zero mean. (Section 3.3.20). The command is only available in
floating point mode.
ENBW[.]
Equivalent noise bandwidth
In fixed point mode, reports the equivalent noise bandwidth of the output low-pass
filters at the current time constant setting in microhertz.
In floating point mode, reports the equivalent noise bandwidth of the output low-pass
filters at the current time constant setting in hertz.
NN[.]
Noise output
In fixed point mode causes the lock-in amplifier to respond with the mean absolute
value of the Y channel output in the range 0 to 12000, full-scale being 10000. If the
mean value of the Y channel output is zero, this is a measure of the output noise.
In floating point mode causes the lock-in amplifier to respond in volts.
DEFEQU [n
n
n
n
n
1
2
3
4
5
The DEFEQU command is used to define the user equations, which take the
following form:
(A
Equation =
Parameter n
is used to specify the equation to be modified, and is either 1 for
1
Equation 1 or 2 for Equation 2.
Parameter n
is used to set the addition/subtraction operator in the numerator
3
according to the following table:-
n
Operator
3
0
Subtraction
1
Addition
The parameters n
according to the following table:
n
Variable
0
X or X1
1
Y or Y1
2
MAG or MAG1
3
PHA or PHA1
n
]
Define user equation
6
B)
C
D
, n
, n
and n
specify the variables A, B, C and D respectively
2
4
5
6
Range
±30000
±30000
0 to 30000
±18000
Chapter 6, COMPUTER OPERATION
6-19
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