On 28/09/11 13:50, Simon Farnsworth wrote:
(note - the CC list is everyone over 50% certainty from get_maintainer.pl)
I'm having problems getting a Hauppauge HVR-1110 card to successfully
tune PAL-D at 85.250 MHz vision frequency; by experimentation, I've
determined that the tda18271 is tuning to a frequency 1.25 MHz lower
than the vision frequency I've requested, so the following workaround
"fixes" it for me.
Are you sure the transmitter concerned doesn't have a VSB filter for an
adjacent DVB-T digital transmitter?
VSB fitlers have been used on UK(PAL-I) transmitters for some time.
From
downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP023.pdf
"To avoid the likelihood of PAL-I interference to DTT transmissions, the
proposal is to use a System B/G VSB filter which provides at least 30 dB
of sideband attenuation at 1.4 MHz below the vision carrier. It is also
necessary to reduce the image sidebands resulting from transmitter
non-linearity, and the method is to fit a high-order bandpass filter at
the transmitter output. Typically, the overall sideband response will be
-2 dB at (fv - 0.75) MHz and -20 dB at (fv - 1.25) MHz, where fv is the
frequency of the vision carrier."
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