Blackmer RMS detector
The Blackmer RMS detector is an electronic true RMS converter invented by David E. Blackmer in 1971. The Blackmer detector, coupled with the Blackmer gain cell, forms the core of the dbx noise reduction system and various professional audio signal processors developed by dbx, Inc.

Unlike earlier RMS detectors that time-averaged algebraic square of input signal, the Blackmer detector performs time-averaging on the logarithm of the input, being the first successful, commercialized instance of log-domain filter. The circuit, created by trial and error, computes root mean squared of various waveforms with high precision, although exact nature of its operation was not known to the inventor. First mathematical analysis of log-domain filtering and mathematical proof of Blackmer's invention were proposed by Robert Adams in 1979; general log-domain filter synthesis theory was developed by Douglas Frey in 1993. 
Q94088970
true RMS converter
Concept
Q5233151
David E. Blackmer
PER
Q22582422
Blackmer gain cell
MISC
Q344489
dbx noise reduction
Concept
Q7248058
professional audio
Concept
Q208163
signal processors
Concept
Q5243771
dbx, Inc.
ORG
Q1130194
time-averaged
Concept
Q111124
algebraic square
Concept
Q11197
logarithm
Concept
None
log-domain filter
UNK
Q2219080
trial and error
Concept
None
root mean squared
UNK
Q7754
mathematical analysis
Concept
Q11538
mathematical proof
Concept
Q18921293
Robert Adams
PER
None
Douglas Frey
UNK
Q94088967
Blackmer RMS detector
Concept
1971-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
1971
DATE
1979-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
1979
DATE
1993-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
1993
DATE
subclass of
discoverer or inventor
time of discovery or invention
used by
notable work
use
manufacturer
manufacturer