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[Discuss-gnuradio] Peak hold spectral plot, TVRX, at 322 MHz, +/- 4MHz.
From: |
Lamar Owen |
Subject: |
[Discuss-gnuradio] Peak hold spectral plot, TVRX, at 322 MHz, +/- 4MHz. |
Date: |
Mon, 7 Nov 2005 13:43:01 -0500 |
User-agent: |
KMail/1.8.3 |
Thought the group would be interested in the attached plots. This is with the
current CVS usrp and gnuradio code, along with the latest distributed fpga
code for the half-band filtering. The plots were generated with an HP 8657B
lab generator, set to -30dBm and stepped in 10kHz increments through the
passband.
One plot is of the TVRX. Also, for comparison, the passband of the 10.7MHz IF
of an Icom R8500 fed into a USRP BasicRX is presented. Note the 'saddle'
shape in the R8500 plot, which is inverted in frequency (making the labels on
the plot misleading, although the center frequency is 322MHz). The TVRX is
about -8dB at +3MHz, and -3dB at -3MHz; the R8500 (a much more expensive
front-end) is a little better, at -5dB +3MHz (remember, the spectrum here is
inverted) and +1dB at -3MHz.
All in all the TVRX fares pretty good here.
--
Lamar Owen
Director of Information Technology
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC 28772
(828)862-5554
www.pari.edu
usrp-tvrx-bandpass-322-8MS-20051105.png
Description: PNG image
usrp-r8500-bandpass-200511051325.png
Description: PNG image
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Lamar Owen <=