Off topic? ...
Looking for circuit for high quality (fixed) signal generator for use with distortion analysis device:
1, 000 cycles +/- 5% , 1.0 VAC +/- 5% output with, hopefully, better than -100 db distortion figure / noise floor.
The idea is to source a clean 1k Htz signal through almost any pre-amp or amplifier for the purposes of comparison using TI ADS1271 Performance Demonstration Kit ( http://focus.ti.com/docs/toolsw/folders/print/ads1271evm-pdk.html ) as per discussion @ http://www.diyaudio.com/forums/showthread.php?s=&threadid=91745&perpage=25&pagenumber=10 (middle of page +)
Since garbage in = garbage out and my el-cheapo bench signal generator leaves a lot to be desired, distortion wise, thinking building a specialized 1k Htz, 1.0 VAC output signal source might be called for. I mean, put a distorted sine wave in and how is one to know for sure about the quality of the sine wave out?
Anyone? Anyone?
Looking for circuit for high quality (fixed) signal generator for use with distortion analysis device:
1, 000 cycles +/- 5% , 1.0 VAC +/- 5% output with, hopefully, better than -100 db distortion figure / noise floor.
The idea is to source a clean 1k Htz signal through almost any pre-amp or amplifier for the purposes of comparison using TI ADS1271 Performance Demonstration Kit ( http://focus.ti.com/docs/toolsw/folders/print/ads1271evm-pdk.html ) as per discussion @ http://www.diyaudio.com/forums/showthread.php?s=&threadid=91745&perpage=25&pagenumber=10 (middle of page +)
Since garbage in = garbage out and my el-cheapo bench signal generator leaves a lot to be desired, distortion wise, thinking building a specialized 1k Htz, 1.0 VAC output signal source might be called for. I mean, put a distorted sine wave in and how is one to know for sure about the quality of the sine wave out?
Anyone? Anyone?
" Perhaps you would like to consider filtering the output of the existing generator with a very sharp low pass filter. "
Of Course! ... I just wanted to try my hand at a "lab bench" special purpose generator. A low pass filter will work I'm sure (a band pass filter being already internal to my el cheapo adjustable unit).
I suppose I could just put that low pass filter in the negative feed back loop of a high gain op-amp ... so's the op-amp "automatically" oscillates at the freq. desired ... this has worked before to rid my garden of gophers = around 18k Htz feeding a few watts into a piezoelectric tweeter = does it every time ... But I was hoping for something a bit more reliable / scientific / cleaner / almost "store bought" and sine wavy ...
Of Course! ... I just wanted to try my hand at a "lab bench" special purpose generator. A low pass filter will work I'm sure (a band pass filter being already internal to my el cheapo adjustable unit).
I suppose I could just put that low pass filter in the negative feed back loop of a high gain op-amp ... so's the op-amp "automatically" oscillates at the freq. desired ... this has worked before to rid my garden of gophers = around 18k Htz feeding a few watts into a piezoelectric tweeter = does it every time
... But I was hoping for something a bit more reliable / scientific / cleaner / almost "store bought" and sine wavy ... I've got a less-than-wonderful generator I use simply because it's more convenient to mess with than either of my two 'big' signal generators. It's got--for want of a better term--a small nipple on top and bottom of the sine wave output. Through long experience, I can gauge the bandwidth of the circuit I'm working with simply by sight. Technically, it's distortion, and I can knock it out with a filter or by adjusting the pots inside the generator, but I kinda like it that way.
It helps that I like nipples to begin with...
Grey
It helps that I like nipples to begin with...
Grey
" ... Through long experience, I can gauge the bandwidth of the circuit I'm working with simply by sight. Technically, it's distortion, and I can knock it out with a filter or by adjusting the pots inside the generator, but I kinda like it that way. ..."
I'm sure that works just fine for you ... but was hoping for a relatively distortion free signal, sans nipples 'cause those little dudes are exactly what will show up on screen from a distortion analyzer like the TI unit above ( http://focus.ti.com/docs/toolsw/folders/print/ads1271evm-pdk.html )
I'm sure that works just fine for you ... but was hoping for a relatively distortion free signal, sans nipples 'cause those little dudes are exactly what will show up on screen from a distortion analyzer like the TI unit above ( http://focus.ti.com/docs/toolsw/folders/print/ads1271evm-pdk.html )
