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Old 15th May 2022, 12:36 am   #34
Synchrodyne
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Join Date: Jan 2009
Location: Papamoa Beach, Bay of Plenty, New Zealand
Posts: 2,943
Default Re: 6-gang FM stereo tuner heads

The attached RCA paper provides a simple “worked example” of the benefits of extra front-end selectivity for FM receivers.

That showed that in the case of bipolar transistors, it was better to place the bandpass at the input and sacrifice some noise performance in favour of better spurious response rejection. When dual-gate mosfets arrived, it was more common to place the bandpass at the interstage, with a single-stage at the input. Presumably the better inherent linearity of the mosfets allowed this. Although there were some mosfet examples with a bandpass input, such as the D&W four-gang front ends (https://vintage-radio.net/forum/show....php?p=1153245).


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