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C Commands Summary
102 MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2
FREQUENCY_OUT
This command allows the user to specify the frequency of the output pulse train available at the variable frequency
(VARF) pin of the I/O strobe connector. This command has no effect on the operation of the GPSCard; it is only
provided for user-determined applications.
The frequency (in Hertz) is calculated according to formulas which require two input parameters (k and p), such
that:
if k =1 or p =1: VARF = 0
if k ≠ 1, p ≠ 1: VARF =
Where:
Fs is the TCXO frequency = 20.000 MHz
k is an integer from 2 to 65536
p is an integer from 2 to 1024
The possible range of output frequencies is 0 - 5 MHz.
The resultant waveform is composed of active-high pulses with a repetition rate as defined above, and a jitter of 50
ns unless k equals 19 999, see the table below for Syntax 1.
The pulse width (seconds) =
The command has two syntactical forms. One is to define a frequency, and the other is to disable this function.
Syntax 1:
Example:
frequency_out 4,8
Syntax 2:
FREQUENCY_OUT K P
Command Range Values
For Jitter Free
Operation
Description
FREQUENCY_OUT - - Command
K 1 - 65 536 19 999 Variable integer
P 1 - 1 024 2 - 1 024 Variable integer
FREQUENCY_OUT keyword
Command Range Values Description
FREQUENCY_OUT - Command
keyword disable The keyword “DISABLE” is the only one defined at this time.
Fs 19 999,×
20 000, kp××
------------------------------------
1 Fs 19999×()20000 k×()⁄[]⁄