File:Audio spectrum analyzer - one filter-rectifier channel.png

From Wikimedia Commons, the free media repository
Jump to navigation Jump to search

Original file ‎(1,271 × 896 pixels, file size: 185 KB, MIME type: image/png)

Captions

Captions

Add a one-line explanation of what this file represents

Summary

[edit]
Description
English: One audio channel (filter + rectifier) for an arduino-based spectrum analyzer
  • Audio bandwidths in the table were selected for the purpose of tuning tape decks, hence quarter-octave resolution in 8-22 kHz area;
  • Filter gains set for pink noise test signal;
  • Rectifier output clamped to max. 5V with zener D1;
  • R2 is the critical minimal load for filter opamp, and should be at least 600 Ohms; more is better but higher R2 will command impractically low C1, C2 at upper octaves;
  • R1 was set to around 20 kOhm so that 12 parallel channels can be driven with a single opamp;
  • Values of C1, C2 (any 5% film formulation) were chosen from E6 range, or what I had in the bins, hence widely varying R1, R2, R3 values from E24 range. Probably nearest E12's will be just as good; the job does not really need E24 precision. Some shift of filter Fc, Q and gain is OK since the test signal is uniform noise.
  • Value of C3 capacitor depends on filter frequency and smoothing methode (all analog, or analog+software) and should ideally be as low as possible - from around 1 uF at 30 Hz to around 0.01 uF at 20 kHz. Even these will sometimes trigger overload protection in rectifier opamp (20 mA), and probably strain power supply, so take care. Sufficient bypass and reservoir capacitors are critical.
  • Choice of opamps is unimportant as long as there's enough gain left at 20 kHz. FET inputs (like TL07x shown here) and low idle currents are desirable but not critical.
Date
Source Own work
Author Retired electrician

[Category:Arduino projects]]

Licensing

[edit]
I, the copyright holder of this work, hereby publish it under the following license:
Creative Commons CC-Zero This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.
The person who associated a work with this deed has dedicated the work to the public domain by waiving all of their rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.

File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current06:09, 5 February 2020Thumbnail for version as of 06:09, 5 February 20201,271 × 896 (185 KB)Retired electrician (talk | contribs){{Information |Description={{en|1=One audio channel (filter + rectifier) for the arduino-based spectrum analyzer. Audio bandwidths in the table were selected for the purpose of tuning tape decks, hence quarter-octave resolution in 8-22 kHz area. Filter gains set for pink noise test signal. Rectifier output clamped to max. 5V with zener D1. Value of C3 capacitor depends on filter frequency and smoothing methode (all analog, or analog+software) and should ideally be as low as possible - from ar...

You cannot overwrite this file.

There are no pages that use this file.

Metadata

This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. The timestamp is only as accurate as the clock in the camera, and it may be completely wrong.

Retrieved from "https://commons.wikimedia.org/w/index.php?title=File:Audio_spectrum_analyzer_-_one_filter-rectifier_channel.png&oldid=906807818"