B
billcalley
- Jan 1, 1970
- 0
Hi All,
I keep reading that the high-gain front-end stages of a microwave
receiver almost completely sets the entire radio's NF and sensitivity,
and that the following stages (the I.F.) have little effect except to
amplify the signal and the noise equally to a higher amplitude for the
radio's detector. This doesn't make complete sense to me, because the
I.F. would have a HUGE effect on the receiver's signal-to-noise ratio,
and therefore its sensitivity, if we simply narrowed the IF's
bandwidth down from, let's say, 1MHz to 1kHz!! So, to me anyway, the
I.F. would have a gigantic effect on the receiver's sensitivity, even
if the front-end had infinite gain. Or am I missing something here?
(BTW: I fully realize we can't just narrow-down the receiver's
bandwidth below the bandwidth of the modulated signal, but I'm just
asking about all this on a theoretical basis to try and understand
"sensitivity" a bit better).
Thanks,
-Bill
I keep reading that the high-gain front-end stages of a microwave
receiver almost completely sets the entire radio's NF and sensitivity,
and that the following stages (the I.F.) have little effect except to
amplify the signal and the noise equally to a higher amplitude for the
radio's detector. This doesn't make complete sense to me, because the
I.F. would have a HUGE effect on the receiver's signal-to-noise ratio,
and therefore its sensitivity, if we simply narrowed the IF's
bandwidth down from, let's say, 1MHz to 1kHz!! So, to me anyway, the
I.F. would have a gigantic effect on the receiver's sensitivity, even
if the front-end had infinite gain. Or am I missing something here?
(BTW: I fully realize we can't just narrow-down the receiver's
bandwidth below the bandwidth of the modulated signal, but I'm just
asking about all this on a theoretical basis to try and understand
"sensitivity" a bit better).
Thanks,
-Bill