Agilent Technologies VXI E1439 - Manual (Page 138)

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Agilent E1439 Programmer's Reference
Functions listed alphabetically
age1439_frequency_setup
Sets all the zoom center frequency parameters. This description also includes information on the
following functions which set or query frequency parameters individually:
age1439_frequency_center sets the center frequency
age1439_frequency_center_get gets the current center frequency
age1439_frequency_cmplxdc selects a complex baseband measurement
age1439_frequency_cmplxdc_get gets the state of the baseband measurement mode
age1439_frequency_sync prepares the module for a synchronous frequency change
age1439_frequency_sync_get gets the state of the synchronous change mode
VXIplug&play Syntax
#include "age1439".h
ViStatus age1439_frequency_setup(ViSession id, ViInt16 cmplxDC, ViInt16 sync, ViReal64
centerFreq);
ViStatus age1439_frequency_center(ViSession id, ViReal64 centerFreq);
ViStatus age1439_frequency_center_get(ViSession id, ViPReal64 centerFreqPtr);
ViStatus age1439_frequency_cmplxdc(ViSession id, ViInt16 cmplxDC);
ViStatus age1439_frequency_cmplxdc_get(ViSession id, ViPInt16 cmplxDCPtr);
ViStatus age1439_frequency_sync(ViSession id, ViInt16 sync);
ViStatus age1439_frequency_sync_get(ViSession id, ViPInt16 syncPtr);
Description
age1439_frequency_setup sets the center frequency of a zoomed measurement. The center of a
frequency band of interest is converted to dc with this function. The frequency transition is phase
continuous unless the center frequency is set to zero in which case the transition may be selected
either to be phase continuous or phase reset. This function may also be used to synchronously
change frequency in multiple-module systems.
Parameters
id is the VXI instrument session pointer returned by the age1439_init function.
centerFreq supplies the center frequency normalized to the sample frequency. It is a number between
−0.5 and
+0.5, which is interpreted as a fraction of the sample frequency. centerFreq is the desired center
frequency divided by the ADC sample frequency. For example, selecting 0.25 with a sample
clock frequency of 100 MHz yields a center frequency of 25 MHz. When using the IF signal path,
the normal range is 0.547 to 0.926 corresponding to 52 to 88 MHz. Your applications should
update this parameter when you change signalPath. The ADC sample frequency is returned by
the age1439_clock_fs_get function. Negative frequencies select the negative image of the signal,
which is spectrally inverted from the input signal.
AGE1439_CENT_FREQ_MIN selects the minimum allowable center frequency.
AGE1439_CENT_FREQ_MAX selects the maximum allowable center frequency.
AGE1439_CENT_FREQ_DEF sets the default center frequency.
centerFreqPtr points to the current actual value of the center frequency (as a fraction of the sample clock
frequency).
cmplxDC selects either a phase continuous or phase reset transition when freq=0.