View Single Post
  #13   Report Post  
Posted to,alt.binaries.schematics.electronic,sci.electronics.basics
Jim Thompson[_3_] Jim Thompson[_3_] is offline
external usenet poster
Posts: 2,181
Default "Random" Circuit Needed.

On Wed, 01 Apr 2015 14:07:40 -0700, RobertMacy

On Wed, 01 Apr 2015 12:08:34 -0700, Jim Thompson


"For a simulation situation..." ;-)

John F and Lasse have provided how to do it.

...Jim Thompson

For simulation I'd use the built-in rand() function of LTspice, if you
want gaussian instead of uniform distribution, use five rand()'s summed
appropriately. You said you like to use PSpice only, so create a text file
to use in a PWL type thingy THEN you can get completel control, likw
distribution and the elusive 1/f etc, any type statistics you want.

For Hardware to not have to go buy much, use the Soundcard and run it
directly with either a repeating pattern of random values, or from a
random number generator to get very long runs. The method of converting
FROM the audio output [BW is 10Hz to approx 100kHz] is left to the
'student'] The point here is that you can get repeatable random sequences
that are completely under your control.

I'm after "random" as in numbers 1-16, which will turn on specific I/Q
components of a modulation "constellation", such as 16-QAM... building
a carrier extractor with AGC and needed a stimulus ;-)

...Jim Thompson
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at | 1962 |

I love to cook with wine. Sometimes I even put it in the food.