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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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16th May 2022, 9:13 pm | #1 |
Pentode
Join Date: Nov 2015
Location: Oxfordshire, UK.
Posts: 171
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Simple De-emphasis/ MPX filter.
Hi, At Retrotech I purchased a few Temic 1894 FM tuner modules, Thanks Radiomobile
I set up a test circuit powered from a 9V battery with a 50K pot and 10K resistor to derive the tuning voltage, a metre of wire served as an antenna. Listening through headphones there was a click each time I connected to the MPX output, I think there might be some DC present so I added a 0.47uF capacitor in line. The modules work really well. I only require a mono output Has anyone had any thoughts on how I best filter out the 19kHz pilot tone and Subcarrier and also provide de-emphasis. Would a simple RC filter work well enough? although I won't be able to hear these signals I don't want to amplify them further. Kind regards Tony |