Narrowband FM Receiver circuit

Apr 18, 2006 10 Replies

Hi group,



Can anyone tell me what it is in the circuit of a NBFM receiver that makes it different from that of a wideband FM receiver?



"Adie"

** The "intermediate frequency" (or IF ) amplification stage has a narrow operating frequency range compared to that used in a broadcast FM receiver.

Often, a NBFM receiver uses the same type of IF amplifier as used in an AM band receiver - ie, operates with a centre frequency of 455 kHz with a 10 kHz bandwidth.

........ Phil

narrow

receiver.

AM

10

None of the second statement is true. The IF can be almost any frequency. The bandwidth of the filter is somewhat larger than 10 khz for a narrow band FM signal. The FM IF is usually ran at a very high gain to strip the AM component of signals (usually noise) . This can not be done with an AM reciever.

The origional question was NBFM not NEFF.

The two main things that come to mind is the bandwidth of the IF filter and the bandwidth of the detector.

"Ralph Mowery" "Phil Allison"

** It is entirely true.

** Sure it can be other frequencies - but it IS "often" 455 kHz.

You are just being an ass.

** NBFM is class of modulation - not a particular bandwidth.

The deviation may be only a few hundred Hz or a few kHz.

You are being a real smartarse now.

Must be one of them smug as hell ham radio pukes.

....... Phil

Some of us smug as hell ham radio pukes are well aware of using a NBFM detector at the end of a "AM" 455kHz I.F. strip. It was still a popular arrangement into the early 50s.

Don't use a shotgun when a rifle will do the job.

Don

Thank you all for your replies. Well at least you've pointed me in the right direction. I think i have a better understanding now. Its nice that you all have an opinion but do we really need to resort to insults? It seems to be commonplace on here. Oh well. Much appreciated.

Adie

Pay no attention to Phil, he's always on the rag. He thinks that his big mouth makes him a man. :(

Service to my country? Been there, Done that, and I\'ve got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida

"Michael A. Terrell"

** Pay no attention to this Terrell asshole.

He is a paranoid delusional schizophrenic.

........ Phil

Don't you have a used vibrator to test, or a damaged toaster to screw?

Service to my country? Been there, Done that, and I\'ve got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida

On Thu, 20 Apr 2006 02:07:41 -0700, Adie wrote: [more trash snipped]

Just put Phalluson in your killfile - it really improves the S/N ratio on the group.

Cheers! Rich

So, where did you graduate med school? Where did you do your residence in psychiatric medicine? Inquiring minds want to know.

I will go so far as to say, however, Michael is an inveterate troll-feeder.

Cheers! Rich

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