RF Generators

[DaWoofer]

Are these the same thing as Function Generators?

 

[Martin.Ca]

Higher frequencies, and only Sine waves, I believe. Used by HAM operators I think.

 

[w1jim]

Higher frequencies, and only Sine waves, I believe. Used by HAM operators I think.

Higher (radio) frequencies, yes. Used by anyone interested in testing / tuning / designing RF (aka Radio Frequency) circuits. Like aligning tuners for example.
JimB

 

[DaWoofer]

So I take it that its to high of a frequency band for FM tuner alignment, is that correct?

 

[dshoaf]

Not necessarily, DaWoofer. RF generators typically have other functions than just creating a sine wave at a specific frequency and at a specific level. RF generators may have different ways to modulate the frequency (AM or FM, for instance). Then there are other signals that may be produced such as the modulated signal of a color TV broadcast - the old analog version.

While you can use an RF sig gen for FM alignment, it first must be able to produce the properly modulated signal to do so, if you are to include stereo demodulators.

So, there's a bit more to it than just a sine wave generator.

Hope that helps....

Cheers,

David

 

[w1jim]

So I take it that its to high of a frequency band for FM tuner alignment, is that correct?

It depends on the frequency of the RF generator but I would think in most cases you should be OK as long as it goes to 110 mhz.
Do you have a good feel for the frequency spectrum?
Here's a wikipedia article that should give you some basic background:
http://en.wikipedia.org/wiki/Radio_frequency

JimB

 

[Jon_Logan]

....you can get function generators to make it to RF frequencies. ...some go to 10MHz etc. Function generators tend to be "dirtier" with higher THD, etc. They tend to have more even amplitude unless you're talking about expensive CW RF generators. If you got a FM range RF generator, it is difficult to use for alignment, unless you really know what you're doing. Suppose you set it to FM modulate: What settings would you use for modulation width? What dBm output setting do you use to measure sensitivity? How can you generate, measure Stereo MPX signals? What separation numbers could be generated from such a setup?

AM is much easier and can be done with a simpler, cheaper device (Function Generator). Generators are nice to have, but if your goal is to get into FM alignment, I'd seek out a Sound Technology 1000A. They have a great MPX generator and all of the hooks you need for FM alignment.

 

[mhardy6647]

You'll need at least a sweep generator to do FM work (not to mention one that is calibrated and in proper working conditon, and ideally with a crystal controlled marker). A regular RF function generator is of somewhat limited usefulness (although it can be used to calibrate an RF receiver if the generator is itself calibrated, or align an AM or SW radio).