[Discuss-gnuradio] reconfigure flow graph with scope app

[Larry Wagner]

Hi -

I have a USRP with 2 RFX2400 daughter cards and need to calibrate the
local oscillator (LO) offset between them. To do this I want to modify
the multi_scope.py example to allow me to reconfigure the flow graph
without stopping. This is based on some external measurement I will do
followed by a keypress and possibly an input using raw_input().

After studying the example Python code fragment taken from the
"Controlling flow graphs" section of

http://gnuradio.org/trac/wiki/Tutorials/WritePythonApplications I was
able to run the code below.

#!/usr/bin/env python

from gnuradio import gr
from gnuradio import audio
import time

class my_top_block(gr.top_block):
    
    def __init__(self):
        
       
gr.top_block.__init__(self)
        
        sampling_freq = 48000
        ampl = 0.1
    
        self.src0 =
gr.sig_source_f(sampling_freq, gr.GR_SIN_WAVE, 350, ampl)
        self.src1 =
gr.sig_source_f(sampling_freq, gr.GR_SIN_WAVE, 440, ampl)
    
        self.adder = gr.add_ff()
        self.sink =
audio.sink(sampling_freq)       

        self.amp =
gr.multiply_const_ff(1) # Define multiplier block
        
        self.connect(self.src0,
(self.adder, 0))
        self.connect(self.src1,
(self.adder, 1))

        self.connect(self.adder,
self.amp, self.sink) # Connect all blocks

    def set_volume(self, volume):
        self.amp.set_k(volume)

        

print
"volume changed to", volume

if __name__ == '__main__':
    
    app = my_top_block()
    app.start()
    raw_input ('Press Enter to change volume: ')
    app.set_volume(2) # Pump up the volume (by factor
2)
    raw_input ('Press Enter to stop: ') 
    app.stop()

#### end of simple code ###

I need help because the statements in the multi_scope.py script are more
complicated. They are:

def main ():
    app = stdgui2.stdapp(my_top_block, "Multi
Scope", nstatus=1)
    app.MainLoop()

if __name__ == '__main__':
    main ()

How can I run the scope app with a keypress and possibly an input using
raw_input()?

Thank you in advance for your help.

 - Larry Wagner