Ametek 7280 Instruction Manual page 154

Chapter 6, COMPUTER OPERATION
NN[.]
DEFEQU [n
6-20
In floating point mode, reports the equivalent noise bandwidth of the output low-pass
filters at the current time constant setting in hertz.
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.
n n n n n ]
1 2 3 4 5 6
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 , n , n
2 4
according to the following table:
n Variable
0 X or X1
1 Y or Y1
2 MAG or MAG1
3 PHA or PHA1
4 ADC1
5 ADC2
6 ADC3
7 ADC4
8 C1
9 C2
10 0
11 1
12 FRQ
13 OSC
Dual modes only:-
14 X2
15 Y2
16 MAG2
17 PHA2
*Parameter n is the only one that can be set to values of 12 or 13.
5
Define user equation
B) × C
⎞
⎟
⎠
D
and n specify the variables A, B, C and D respectively
5 6
Range
±30000
±30000
0 to 30000
±18000
±10000
±10000
±10000
±10000
0 to 100000
0 to 100000
zero
unity
0 to 2000000000 (i.e. reference frequency in mHz)*
0 to 2000000000 (i.e. oscillator frequency in mHz)*
±30000
±30000
0 to 30000
±18000