Intermediate Frequency choices

Indeed. It's generally easier to write a program, validate it, and run it once than it is do do the work on paper once.

(You can also do it graphically, which does a nice job of showing where the spurs are going to end up in the final product).

My only point is that having an intermod program isn't magic; it took me more work to fling together the spreadsheet that estimates my quarterly taxes than it would take to make an intermod-predicting program.

On Sun, 20 Sep 2009 15:57:04 -0700, ssylee wrote: (top posting fixed)

Well, is it easier to build a 500Hz wide filter at an IF of 455kHz or

And if your IF is 455kHz where's the image frequency for an RF of 2MHz? What if your IF is 75MHz?

Answer those questions, and you're going to be a lot closer to understanding the IF frequency tradeoffs.

--- Yup. In the superheterodyne case, where the LO is higher than the carrier, the image lies at fC + 2IF while in the subheterodyne, where the LO is lower than the carrier, it lies at fC - 2IF.

I described the superheterodyne case and showed why your description of the location of the image for both the superheterodyne and subheterodyne cases was

--- ???

---

--- Typo.... Rrriiggghhhttt!!!

---

--- Naturally, now that you've learned the trick, it was a typo.

Before that, it was an *****ERROR*****

Agreed. Especially since there are all those nice performance measurements in the Mini-Circuits catalogue to check it against.

Cheers

Phil Hobbs

A high unloaded Q and a low (heavily) loaded Q is a good thing, since this does not cause excessive losses and hence bad noise figures at least at frequencies, at which the noise figure is of any importance (say above 2 MHz).

Paul

Yes. My mind is usually thinking of active filters, which is not the case in IF stages.

=A0you

lar

Mr. Allison, it is time for your enema.

"John Fields"

Go drop dead - you stinking pile of psychotic autistic shit !!!

.... Phil

Don't forget double or triple conversion.

might one

would

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given

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frequency

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frequency."

understand?

Was the L-Band stuff on chip of off chip?

one

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s RF

understand?

=A0 =A0 =A0 ...Jim Thompson

=A0 =A0 =A0 ...Jim Thompson

Garmn -> GRMN - Global Risk Management Network?

understand?

Straight into a mixer, no RF gain. ...Jim Thompson

Not my understanding of the term "superheterodyne".

Superheterodyne - abbreviation of "Supersonic Heterodyne", ie. A heterodyning system where the resultant "beat" frequency is supersonic, that is above the audible range.

I've never heard the term "subheterodyne".

IME, the cases where the LO lies above or below the carrier frequency and the IF is supersonic are *both* "superheterodyne*.

As an aside, it used to be a common practice with some double conversion mobile receivers, to choose to crystal the second LO either above or below the first IF to avoid birdies on some channels.