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Revision 3 (max, 04/22/2017 04:04 PM) → Revision 4/30 (max, 04/22/2017 04:04 PM)
= Signal Scope =
== Installation ==
Before running the scope app, check that the following packages are also installed:
* GNU Radio
* The op25 blocks
* Frank's gr-fsk4 block
* The op25 repeater block
Other than these pre-requisites, no special setup or installation is needed.
There are two overall options depending on your hardware (USRP or disc-tap).
== Running with the disc-tap option ==
The signal scope does not require the USRP. If you have a discriminator-tapped receiver, use the "-a" option:
{{{
./scope.py -a -v 25
}}}
== Running with the USRP ==
It's helpful to find out the current calibration error beforehand (I use kalibrate), for example, +1234 hertz:
{{{
./scope.py -f 412.34e6 -RA -g 65 -c 1234 -v 25
}}}
In USRP mode, several additional program functions are enabled (spectrum FFT, constellation diagram, PSK demod, and iDEN correlation).
== Feature overview ==
* Spectrum plot
* Baseband oscilloscope
* Eye Pattern Diagram (Datascope) display supporting several standard symbol rates
* Constellation Diagrams
* Demodulated Symbol Output
* Correlation
* Direct-frequency entry, signal gain and fine-tuning controls
* User-selectable demodulator (FSK4 or QPSK)
== Spectrum Display ==
[[Image(a.png)]]
The controls arranged along the bottom of the page are:
* Frequency: to retune, type the new frequency here and press ENTER
* Signal Gain: adjusts the baseband (demodulated) signal level
* Fine Tune: adjusts tuning frequency over +/- 3000 Hz range
* Demod: Selects demodulator (currently used in Demodulated Symbols only)
Except for the signal gain control, these controls are only available in USRP RX mode.
== Eye Pattern Diagrams ==
The scope input source can be connected either before or after the symbol filter using the Viewpoint toggle.
Also the proper speed must be selected from the available options.
[[Image(b.png)]]
== Constellation Diagram ==
[[Image(c.png)]]
== Demodulated Symbols ==
[[Image(d.png)]]
== Correlation ==
[[Image(e.png)]]
