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Chapter 6, COMPUTER OPERATION
FMFILTER [n]
FMSPANF[.] [n] Oscillator frequency modulation span frequency command
FMVSPAN[.] [n] Oscillator frequency modulation voltage span command
6.7.07 Analog Outputs
CH n
6-24
Oscillator frequency modulation filter control command
The value of n sets the oscillator frequency modulation voltage low-pass filter
control in the range 0 to 10. The value of 0 gives the widest bandwidth for this filter,
with the value of 10 the lowest.
In fixed point mode n sets the oscillator frequency-modulation span frequency in
mHz. The range of n is 0 to 125,000,000 representing 0 to ± 125 kHz; in floating
point mode n sets the span frequency in Hz. The range of n is 0 to 1.25E5.
Note: The center frequency
limits of the oscillator ( 0 to 250 kHz). Hence the center frequency plus the span
frequency cannot exceed 250.0 kHz and the center frequency must be greater than
or equal to the span frequency. For example, at 125 kHz center frequency the
maximum span frequency is
span frequency is
10 kHz; at 240 kHz center frequency the maximum span
frequency is also
10 kHz. When setting the center frequency and span frequency
under computer control it is recommended to first set the span frequency to zero
followed by the center frequency to the required value and finally the span
frequency to the required value. This will avoid potential problems with the new
center frequency being rejected because it is not a legal value when compared with
the old span frequency.
The value of n sets the oscillator frequency modulation span voltage; in fixed point
mode n is an integer in the range 0 to +10000, corresponding to a range from
0.000 V to 10.000 V, and in floating point mode it is in volts.
Note: The span voltage plus the center voltage cannot exceed
[n
]
DAC analog output control
1
2
Defines what outputs appear on the DAC1, DAC2, DAC3 and DAC4 connectors on
the rear panel.
n
Signal (DAC1)
2
0
X % (2.5 V FS)
1
Noise % (2.5 V FS)
2
Ratio: (10 × X%/ADC 1)
(10 X%/ADC1)
3
Log Ratio: log
10
4
Equation 1
5
Equation 2
6
User DAC1
7
Main signal channel ADC output (digital signal monitor 1)
8
Magnitude2 % (2.5 V FS) (dual mode only)
n
Signal (DAC2)
2
0
Y % (2.5 V FS)
1
Noise % (2.5 V FS)
2
Ratio: (10 × X%/ADC 1)
(10 X%/ADC1)
3
Log Ratio: log
10
4
Equation 1
the span frequency must not exceed the frequency
125 kHz; at 10k Hz center frequency the maximum
10.000 V
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