John Woodgate wrote:
I read in alt.binaries.schematics.electronic that Albert
wrote (in ) about 'MK484
single chip AM radio question', on Mon, 4 Apr 2005:

I hope to use the MK484 single chip AM radio at 20 kilohertz for a
very low power receiver. The spec sheet says it only goes down to 150
kilohertz however.


Is there any reason to suppose it contains a coupling capacitor or
something that would limit the low-frequency response? It seems rather
unlikely. But the definitive test invokes a little-used technique in
these days of calculations and simulations. It's known as 'trying it'. (;-)

It isn't as if testing at 20 kHz is rocket science, after all.

Since this is a superhet chip (IIRC), the problem is more likely one of LO
bleed through into the IF. The LO frequency would have to be on the
high side of the receive frequency, so in this case, with a 455Khz IF,
the LO would be at 475Khz. The LO signal bleeding through the IF filter
would probably be as strong, or stronger than the 20KHz signal you were
intending on receiving.

-Chuck