222 HARTREY AVE.. EVANSTON. IL. 60204 U.S.A.
1
:!EtT MODEL 202
AREA CODE 312/866.2200 CABLE: SHUREMICRO MICROPHONE
TWX: 910.231-0048 TELEX: 72-4381
I
CERAMIC NOISE-CANCELING COMMUNICATIONS MICROPHONE
Microphone
Features:
GENERAL
The Model 202 ceramic, noise-canceling communi-
cations microphone is designed for clear, crisp,
natural voice response in even the noisiest surround-
ings. Noise cancellation is provided through the
combination of highly directional operation and supe-
rior discrimination against noise from distant sources
over a wide frequency range. The Model 202 is partic-
ularly suited for mobile use where wind, traffic, engine,
or other background noise may otherwise interfere
with voice transmission.
Model 202 is relatively immune to adverse tempera-
ture and humidity, and it will operate in temperatures
to 71°C (160°F).
The microphone is high impedance, and is equipped
with a heavy duty push-to-talk switch to control the
microphone circuit and an external relay or switching
circuit.
Model 202 fits naturally and comfortably in the
hand. The exclusive ARMO-DUR@case is immune to
oil, grease, fumes, salt spray, sun, rust, and corrosion
-and is outstanding in its ability to resist mechanical
shocks and vibration, It is designed to withstand
rigorous operating conditions and constant use.
Highly intelligible voice response
w
Effective noise cancellation
Reliable, high-output ceramic cartridge
m
Tough, rubber-jacketed, four-conductor coiled
cable
w
Rugged ARMO-DUR case
w
Mounting bracket supplied-fits hang-up button
on microphone
NOISE CANCELLATION
The important characteristics contributing to noise
cancellation and clear speech transmission in the
Model 202 are shaped frequency response, direction-
ality, and distance discrimination.
Shaped Frequency Response: The acoustical re-
sponse is arranged to optimize performance in the
critical voice frequency range of 200 to 4,000 Hz. The
result is the reduction in pickup of sounds outside the
desired frequency range and proper control of those
sounds within the desired range.
Directionality: Through its inherent directional
properties, Model 202 reduces pickup of off-axis
sounds, all sounds extraneous to the user's voice.
Distance Discrimination: The Model 202 discrim-
inates against sounds arriving from a distance in favor
of sounds from a near source. The microphone oper-
ates on the pressure gradient principle. Two sound
entry ports spaced a small distance apart produce, by
means of phase cancellation, reduction of sensitivity
to all distant sounds.
OPERATION
In order to obtain the best noise-canceling perform-
ance with the Model 202, "close-talking" is required.
The lips must be as close as possible to the micro-
phone grille and directly facing it. For greatest dis-
crimination between voice sounds and background
noise, do not hold the microphone more than 25 mm
(1 in.) from the mouth.
No polarizing voltage is required for ceramic micro-
phones. Ceramic microphones may be seriously dam-
aged if accidentally connected to loudspeaker or
power supply outlets carrying high voltage. Check
your connections carefully. When used near a radio
transmitter, cable should be kept to the minimum
length consistent with placement requirements.
Model 202 will operate satisfactorily under all ordi-
nary conditions of humidity, heat, and cold. Dropping
the microphone or other such severe mechanical
shocks should be avoided.
Copyright
1979,
Shure
Brothers
Inc.
27A267 (SI)
Printed
in
U.S.A.
U.S.
Patent
0194,749
