INSTRUCTION MANUAL
model WM-220
GENERAL DESCRIPTION
TOA WIRELESS MICROPHONE
The TOA WM-220 is a crystal controlled hand-held type wireless microphone designed for
operation on a specific frequency from 30MHz to 50MHz.
FEATURES
1. The WM-220 weighs just 170g and small (25.3 diameter x 167mm) enough to fit into a
shirt pocket.
2. Three (3) "AAA" size alkaline batteries power the WM-220 continuously for 30 hours.
3. Adoption of crystal controlled direct frequency modulation system keeps the oscil-
lation frequency stable against the change of ambient temperature or voltage
fluctuation.
4. Dynamic range can be greatly increased, without incorporating compressor and
expander, for the pickup of audio signals from a quiet whisper to a full "lung
power" without overmodulation and distortion. Its unique circuit design also
assures the excellent signal-to-noise ratio.
5. Human body-effect-free design assures dependable operation of the WM-220.
6. Two (2) LED's are provided for easy-to-see monitoring of the battery consumption.
7. A built-in AGC circuit acts only for excessive input, suppressing a distortion
spontaneously. The AGC does not act for normal input, enabling the WM-220 to
provide the same performance as that of the "wired" microphone.
8. A non-glare finished microphone body is made of metal and can fit in one's palm.
9. Switching noise produced when turning switch on and off is extremely low, virtually
raising no problem for practical use.
FREQUENCY RESPONSE CURVE
Through the combination use of the WM-220 and the WT-720 receiver, the frequency
response has been measured by providing a sinewave of 94dB SPL from a point 50 cm
distant from the microphone head.
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