SMB/EO1 Series
LECTROSONICS, INC.
4
Variable 1.8 - 4v
+6V
+5V
5V
Regulator
Servo Bias Input
The voltage and current requirements of the wide
variety of electret microphones used in professional
applications has caused confusion and compromises
in the wiring needed for wireless transmitters. To ad
dress this problem, the unique Servo Bias input circuit
provides an automatically regulated voltage over a
very wide range of current for compatibility with all
microphones.
Digital Hybrid Wireless
®
Technology
All wireless links suffer from channel noise to some
degree, and all wireless microphone systems seek to
minimize the impact of that noise on the desired sig
nal. Conventional analog systems use compandors for
enhanced dynamic range, at the cost of subtle artifacts
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tems defeat the noise by sending the audio information
in digital form, at the cost of some combination of power,
bandwidth and resistance to interference.
Digital Hybrid systems overcome channel noise in
a dramatically new way, digitally encoding the audio
in the transmitter and decoding it in the receiver, yet
still sending the encoded information via an analog
FM wireless link. This proprietary algorithm is not a
digital implementation of an analog compandor but a
technique that can be accomplished only in the digital
domain, even though the inputs and outputs are
analog.
Because it uses an analog FM link, the Digital Hybrid
system enjoys all the benefits of conventional FM
wireless systems and it does away with the analog
compandor and its artifacts.
General Technical Description
No Pre-Emphasis/De-Emphasis
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ratio high enough to preclude the need for conventional
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emphasis (HF roll off) in the receiver. This eliminates
the potential for distortion of signals with abundant
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Low Frequency Roll-Off
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point at 35, 50, 70, 100, 120 and 150 Hz to control
subsonic and very low frequency audio content in
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depending upon the low frequency response of the
microphone.
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mitter into limiting, or in the case of high level sound
systems, can even cause damage to loudspeaker
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while listening as the system is operating.
Input Limiter
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more than 30 dB for excellent overload protection. A
dual release envelope makes the limiter acoustically
transparent while maintaining low distortion. It can be
thought of as two limiters in series, a fast attack and
release limiter followed by a slow attack and release
limiter. The limiter recovers quickly from brief tran
sients, with no audible side effects, and also recov
ers slowly from sustained high levels to keep audio
distortion low while preserving short term dynamics.
