Setting The Allan Deviation Τ Value; Setting Frequency Counter's Reference Frequency; Retrieving Status Information - Symmetricom 5120A Operation And Maintenance Manual

For more general information about the time constant see
on page 41.
7.2.6.4 Setting the Allan Deviation τ
You can set the τ
set tau0 <value>
Where the <value> parameter is set to:
A fixed floating point number
0.001, 0.01, 0.1, or 1 (seconds)
The Allan deviation plot or table can be printed for a single τ
deviation plot for a τ
set tau0 0.01
print adevplot
For more information about printing from the network, see
Port" on page 60.
To determine the current τ
value in the format used by the set tau0 command.

7.2.6.5 Setting Frequency Counter's Reference Frequency

See "Chapter 5, Configuring the Frequency Counter"
frequency counter.
To automatically set the reference frequency each time data collection starts, enter:
set referencefreq auto
To manually set it to a more precise value, provide the frequency in MHz as the last parameter to
the set referencefreq command. To set it to 5.0000003 MHz enter:
set referencefreq 5.0000003
Future show fcounter commands return the averages calculated using the new reference
frequency. The user interface table is also updated immediately. Note that show fcounter can be
used to determine what the current reference frequency is.
The reference frequency is applicable only to external signals connected to the Reference port, it
does not affect the reference frequency used in the internal reference mode featured by the 5120A-
01. The set referencefreq command can be sent while a 5120A-01 is operating in internal
reference mode, it will take effect the next time data is collected using an external reference signal.

7.2.7 Retrieving Status Information

To determine the current data collection state, enter show state. The command outputs the current
state and time constant. If the test set is in the Collecting state when the command is issued, the
duration of data collection is also output. For general information see
page 13.
5120A/5115A Operations and Maintenance Manual
Value
0
value using the following command:
0
of 10 ms, issue the following commands:
0
value, use the show tau0 command. The test set will return the current
0
"Chapter 5, Setting the Time Constant"
value only. To print the Allan
0
"7.2.4 Printing from the Command
on page 49 for general information about the
"3.2.1 Collecting State" on
63