[Discuss-gnuradio] High-speed captures of high-quality signals available.

[Lamar Owen]

After some prompting, I have put together three high-quality signal captures 
for your enjoyment.  The captures were made using the commandline:
./usrp_rx_cfile.py -o filename.dat -d8

Signal generator is a lab-grade HP8657B, recently calibrated, with output 
level set at -10dBm, and with a 20dB attenuator at the USRP (-30dBm signal, 
theoretically).  The four frequencies used were 100kHz, 500kHz, 1MHz, and 
2MHz.  The DDC was set to zero.

Filenames are:
1MHz-sin-usrp-hp8657b-20050421.dat.bz2
2MHz-sin-usrp-hp8657b-20050421.dat.bz2
100KHz-sin-usrp-hp8657b-20050421.dat.bz2
500KHz-sin-usrp-hp8657b-20050421.dat.bz2

All are available at http://www.lamarowen.net/files/

They average 1.5-2.5MB bzip compressed; uncompressed they are roughly ten 
times that size.

USRP serial# 179 was used to make these captures, using a BasicRX module.

The results are encouraging.  Previously, I had used my cheap Elenco function 
generator; come to find out that its output is horrible and shouldn't be used 
for basically anything.  Probably a bad output coupling cap or something.

The HP8657B is only rated to go down to 0.1MHz, but it does go up to 2060MHz, 
which is the range in which it gets used at PARI (we calibrate using it at 
1420MHz and -122dBm).    By comparing output levels one could look at 
frequency response to a degree.  If desired, I can use our noise source as 
well; it's calibrated flat from about 1MHz to over 100MHz.
-- 
Lamar Owen
Director of Information Technology
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC  28772
(828)862-5554
www.pari.edu