More than averagely fun & disparate collection of Level, Absolute Value, Peak and RMS Detectors,

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More than averagely fun & disparate collection of Level, Absolute Value, Peak and RMS Detectors,

RussellMc
More than averagely fun & disparate collection of  Level, Absolute Value,
Peak and RMS Detectors, and a bit more besides.
Some oldies but goodies. Some just oldies :-).
Level Detectors, Absolute Value, Peak and RMS
<http://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=6&t=111&sid=917b1d201051cb2f9c42b44ca7cda1e5>

     http://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=6&t=111

_____________

While obvious, I love the sheer simplicity of "A comparator-based peak
detector using an LM339 open collector output"
Non OC output could be accommodated with a diode from output to cap (which
turns it back into a "usual" implementation.)

Ken: Note "Diode simulator reduces forward drop to 0.04V," Eng, EDN July
20, 1992." - the external supplies use is cheating, but 'simplifies
things'.
Series opposed FETs of same type with gates tied give a proper 'semi-ideal'
diode diode, subject to properly protecting IC against switched V.

.

                         Russell
_____________________________


*Partial list of the text between the many images as an indication of
what's there.*

Pro Audio Design Forum
Pro Audio Circuit Design and Discussion

Level Detectors, Absolute Value, Peak and RMS
This is a collection in pictures. I'll add text later.


"Absolute Value Circuit Delivers High Bandwidth," Ron Mancini, EDN, July
2004.
Analog Devices AD536 Absolute Value
A comparator-based peak detector using an LM339 open collector output.
A comparator-based peak detector with NPN Boost transistors.
"Diode simulator reduces forward drop to 0.04V," Eng, EDN July 20, 1992.
"Frequency doubler gives pure sine wave," Electronic Design, June 21, 1975.
The discontinued Precision Monolithics GAP-01 used as an absolute value
rectifier.
A two-color overload indicator using a comparator-based peak detector.
A peak flasher. Note the pinout error on the bottom TL074.
A log peak detector. Two channels shown. Crazynightowl may recognize this
one.
Peak-to-peak detector
The AD823 op amp used as a rectifier
AD823 rectifier output
D-R Compressor Shunt rectifier
An early dbx rms detector from the patent application.
A dbx rms detector using the CA3083.
Stephen Woodward, rms detector with differential input
dbx 902 rms using transistor array
bcarso symmetrical rectifier
Graeme symmetrical rectifier
  Note: The above rectifier circuit has been attributed to SSL by Rod
Elliot but I first saw it in the 1973 edition of "Applications of
Operational Amplifiers," Jerald Graeme, Burrr Brown. It is used in the SSL
Phase Meter.
Boss SG-1 Rectifier
"Dual Polarity Peak Detector Operates From Single Supply," Chester Simpson,
EDN, May 12, 1994.
    Full pdf: http://www.waynekirkwood.com/s/pdf ... 2_1994.pdf
Full Wave Precision Rectifier CW Beal Wireless World July 1982

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This one shows how to select positive, negative, or full-wave peaks:
   http://www.edn.com/article/CA6339250.ht ... ryid=44217
And from the reference, a neat envelope follower technique (scroll down to
2nd article):
     http://www.edn.com/contents/s/122602di.pdf
Here's another one I just found in a stomp box:
Biased Diode Rectifier
"Applications of Operational Amplifiers," Third Generation Techniques,"
Jerald Graeme, Burr-Brown, 1973, Figure 4.18.
Using a THAT340 with D1 and D2 as diode-connected transistors this circuit
rocks as a half-wave rectifier.
I used an LME49860.
A second summation stage, not shown, makes this an absolute value circuit.
I lowered the 10K bias resistors to 2K2.
D1 should thermally track Q1 and D2 should track Q2 but D1/Q1 and D2/Q2 do
not need to be in the same package.
Visit RockmoreLabs on Etsy https://www.etsy.com/shop/RockmoreLabs
http://www.linkedin.com/in/waynekirkwood
http://www.ka-electronics.com
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