> "Jim B." <[EMAIL PROTECTED]> wrote: > > Jeff DePolo wrote: > >> Real world transmitters always have limiters. Those DO > >> change flatness. > > That keeps throwing me. I hear 'limiter' and I go towards the > receiver. A limiter is a low IF amplifier that is biased to go > into saturation with very little input.
It's one application for a limiter... you can also have a limiter in the audio stage and at the front end of a transmitter in the modulator section (typical). > This clips off amplitude peaks, on even weak signals, which are > going to be generated by either man-made or natural > noise. Thus the advantage of using FM in the first place. Don't make the mistake of using "clip" for every limiter ap you run into. It's a description. In the case of an IF Limiter it's probably just fine. In the case of an audio limiter you don't have to clip the signal. > I'm used to calling what you describe a 'clipper' or, in > Motorola terminology, an IDC circuit. > Ah well, you say 'tomato' and I say 'rutabaga'...;cD > -- > Jim Barbour > WD8CHL Depending on how the circuit is designed... a tx limiter can be set up to hard compress, which some people interchange as a limiter function. You'll probably find most compress type limiters also follow up with a "hard fixed" limiter of some type. cheers, s.
