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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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23rd Jan 2019, 1:58 pm | #1 |
Triode
Join Date: Aug 2007
Location: Altrincham, Greater Manchester, UK.
Posts: 31
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Racal RA1772 IF Crystal Filter profiles. Testing. Help wanted.
Hi,
I am testing a number of 1.4Mhz I.F. Crystal Filters as used on the Racal RA1700 series radios, RA1772, with a Spectrum Analyser and Traking Gene. I have tested a number of symmetrical filters and all have a similar shape, profile and the Spectrum Analyser displays the corresponding BW for each filter tested eg 400Hz 9Khz, 6Khz etc. All OK However I have one filter marked USB 3Khz, on test, the filter shape/ response is the same as the symmetrical filters (ie non LSB/USB filters). My Q., is this correct? Or should I see a different shape for this Filter as I assume it should have an Asymetrical response. Or Should a USB filter response just be shifted away from the 1.4Mhz centre.? Any help gratefully received. Stuart |