Digital Standard GPS SMIQ
1125.5555.03 E-92.338
Fig. 2-213 DIGITAL STD - GPS menu
DOPPLER SHIFT
Sets the desired Doppler shift of the GPS signal. This affects the symbol rate
used as well as the frequency shift of the carrier signal.
IEC/IEEE-bus command :SOUR:GPS:DSH 0
SYMBOL RATE
Sets the basic value of the symbol rate for zero Doppler, i.e. without Doppler
shift. This value is used to calculate the actual symbol rate as a function of the
Doppler shift set. At a Doppler shift of 0 Hz, the values of SYMBOL RATE and
RESULTING SYMBOL RATE (see below) are identical.
IEC/IEEE-bus command:SOUR:GPS:SRAT 1023000.0
RESULTING SYMBOL
RATE
Displays the physical symbol rate currently used. The value is obtained from
the set frequency, the Doppler shift and the set basic symbol rate for zero
Doppler according to the following equation:
÷
÷
ø
ö
ç
ç
è
æ
+∗=
FREQ
f
ff
Doppler
SymbolSymbol
rZeroDoppleresulting
1
IEC/IEEE-bus command:SOUR:GPS:CURR:SRAT?
RESULTING
FREQUENCY
Displays the physical carrier frequency currently output. The value is obtained
from the sum of the set frequency under FREQ and Doppler shift according to
the following equation:
Doppler
fFREQf +=
IEC/IEEE-bus command :SOUR:GPS:CURR:FREQ?
C/A CODE
Sets the C/A code for spreading the navigation data. This clearly defines the
simulated GPS satellite.
IEC/IEEE-bus command :SOUR:GPS:CODE 1
NAVIGATION DATA
SOURCE
Selects the navigation data source. Either simple bit patterns (see PATTERN)
or more complex data lists (see DATA LIST) with GPS-specific navigation data
(ephemeris and almanac), for example, can be selected.
IEC/IEEE-bus command :SOUR:GPS:DATA PATT
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