Oscilloscope mode
The Zpectrometer micros can take time series data for individual
lags. First, set the master and quad switching mode:
titania>
telnet zpectrometer1.gbt.nrao.edu
zpec> b 1
zpec> poke
0.4 1
zpec> quit
If the backend is not zpectrometer1, synchronize the test unit (beN in
this example) to the master and set the matching switching mode:
titania>
telnet zpectrometerN.gbt.nrao.edu
zpec> sync
zpec> poke
0.4 1
zpec> quit
Now set up to write the file to disk with name filename
(e.g. totpwr1.dat), then start the oscilloscope mode on the
micro. In this example, look at all lags, integrating for 20
cycles of 11.52 ms each (0.230 s), with 504 samples (116.1 s total
time):
titania>
source ~/wasp2/wasp_start
titania>
zpec -a zpectrometerN.gbt.nrao.edu filename
zpec> o
0-255 20 504
let it run until it finishes dumping numbers to the screen (and
possibly an error message), then terminate and close files with
zpec>
ctrl-D
The maximum product of number of lags times the number of samples is
2^17 = 131,072, or
- 256 * 512 (maximum)
- 256 * 504 (for Allen variance)
- 121 * 1080 (for Allen variance)
- 52 * 2520 (for Allen variance)
An example of a non-contiguous set of lags is 0-16,18,250,252-255
(no spaces)
The longest time bin is 1/18th of the longest time with the current
builds of the Allen variance routines, so for sampling all lags:
- 0.01152 * 622 * 504 gives 504 7.2 second samples over 3611 sec (1 hour) with a maximum lag time of 200.6 sec
- 0.01152 * 311 * 504 gives 504 3.6 second samples over 1806 sec (30 min) with a maximum lag time of 100.3 sec
- 0.01152 * 186 * 504 gives 504 2.1 second samples over 1080 sec (18 min) with a maximum lag time of 60.0 sec
Questions or comments? Please contact Andrew Harris.