Re: Basic USRP AM Transmission


#1

----- Original Message -----
From: Martin D. removed_email_address@domain.invalid
Date: Monday, April 17, 2006 3:06 pm
Subject: Re: [Discuss-gnuradio] Basic USRP AM Transmission

doing wrong? Does my output need filtering before connecting to
What is the sample_rate of the audio file
What is you interpolation rate of the usrp
What is the duc frequency of your usrp.

I have the file source sampled at 32kS/s

I use the following code for setting up my usrp:

    self.dac_rate = self.u.dac_rate()                    # 128 MS/s
    self.usrp_interp = 400
    self.u.set_interp_rate(self.usrp_interp)
    self.usrp_rate = self.dac_rate / self.usrp_interp    # 320 kS/s
    self.sw_interp = 10
    self.audio_rate = self.usrp_rate / self.sw_interp    # 32 kS/s

    # determine the daughterboard subdevice we're using
    if options.tx_subdev_spec is None:
        options.tx_subdev_spec = usrp.pick_tx_subdevice(self.u)

    m = usrp.determine_tx_mux_value(self.u, options.tx_subdev_spec)
    self.u.set_mux(m)
    self.subdev = usrp.selected_subdev(self.u, 

options.tx_subdev_spec)
print “Using TX d’board %s” % (self.subdev.side_and_name(),)

    self.subdev.set_gain(self.subdev.gain_range()[1])    # set max

Tx gain
self.set_freq(options.freq)
self.subdev.set_enable(True) # enable
transmitter

This is the same code I used for both a NFM and WFM transmitter, both of
which appeared to transmit without problems.

Sincerely,
~Chris~


#2

Robert R. wrote:

doing wrong? Does my output need filtering before connecting to
440Hz tone
I use the following code for setting up my usrp:
options.tx_subdev_spec = usrp.pick_tx_subdevice(self.u)
transmitter

This is the same code I used for both a NFM and WFM transmitter, both of
which appeared to transmit without problems.
But do you actually put a software interpolator in there somewhere.
I didn’t see any in your code:

self.connect (src, const)
self.connect (const, conv)
self.connect (conv, gain)
self.connect (gain, self.u)
should be:
self.connect (src, const)
self.connect (const, conv)
self.connect (conv, gain)
self.connect (gain, softwareinterpolator)
self.connect(softwareinterpolator,self.u)

greetings,
Martin