Building a project which requires alignment and says to use a audio generator, which basically looks like a function generator, which I do have. For various sections of the alignment it states, set the audio generator to 455KHz, etc.
Are they one in the same? I am thinking that the audio generator has some type of "noise" which the function generator does not?
Thanks!
When you get to 455 khz I would think they would say RF generator. Anyway, an audio generator is usually tought of as a signal generator that goes from around 20 hz to maybe 100 khz or less. If you set your function generator to a sine wave function and to the correct frequency and output level it will work just as well. You may think of the audio generator as just part of the function generator. Function generators usually have more options than the audio generators.
I would expect an audio signal generator to just produce sine waves over a range of 10 - 30,000 Hz, or so. A signal generator for 455 KHz would more likely be called an RF signal generator, and would only make sine waves.
A function generator would produce signals from 1Hz (or less) up to 20
- 50 MHz, and should be able to produce sine, square or triangle waves, or pulses. A function generator should be able to replace an audio or RF generator in most applications (up to its maximum frequency).
An audio generator may have lower distortion on its sine wave than the function generator, which may be significant if you are doing distortion measurements
-- Peter Bennett, VE7CEI peterbb4 (at) interchange.ubc.ca new newsgroup users info : http://vancouver-webpages.com/nnq GPS and NMEA info: http://vancouver-webpages.com/peter Vancouver Power Squadron: http://vancouver.powersquadron.ca
It's a matter of how the signals are generated. An audio generator usually uses a sine wave oscillator such as a Wien Bridge to generate its signals while a function generator uses integration and rounding of a sawtooth wave to generate its sine output. There are subtle differences in the distortion, points of inflection and other issues than distinguish the waveforms. None of that should matter to you as long as you can get a stable, accurate frequency. Most function generators don't have very precise frquency setting knobs making it hard to get an exact frequency setting. You should use a counter to set the frequency as closely as possible. This frequency, 455KHz is the I-F frequency for a standard AM receiver. It should be accurately set to avoid spurious responses and other problems. Bob
Audio sig gens wil certainly have sinewave and usually square wave outputs. Function generators will normally have triangle and pulse outputs too and maybe a mark-space adjustment.
A 'noise generator' is another thing altogether.
Graham
To extend what others have already said, note that function generators intrinsically produce triangle (and square) waves, and have to be shaped to sine waves. The sine wave distortion is typically 1%. An audio sine generator typically has distortion below
0.1% in the 20-20000 Hz range. Usually, either type is limited to a MHz or so.If you need a signal generator for conventional audio frequencies (20-20000 Hz), you might want to check out my freeware DaqGen signal generator software. It can use any Windows computer and sound card. Sine distortion is limited by the card, but can easily be better than typical benchtop models. Besides sine waves, it can create most any waveform you need, including different types of random noise and arbitrary waveforms. You can combine 4 separate streams per output channel, and each stream can use any or all of several modulation types, including Burst, AM, FM, PM, or Sweep. I'd be glad to answer any questions about it.
Best regards,
Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.