4
Passive versions of these headsets already exhibit excellent noise reduction ratings
(NRR). Test measurements indicate an increase in attenuation at lower frequencies
when ENC is switched on. At the present time there is no ANSI test standard for
independent measuring of the effectiveness of Electronic Noise Cancellation.
Fail-safe:
An important product feature is true “fail-safe” operation. By having dual earphone
drivers, which are electronically independent, no interruption of communication can
result from failure of the ENC system or its power source.
Headset:
Sensitivity: 90dB +- 5dB SPL on flat plate coupler, re 1mW input @ 1 KHz.
Frequency Response: 350-3,000 Hz +- 6dB re 1 KHz.
Impedance: Monaural, 150 Ω nominal; Stereo, 300 Ω nominal
per side. (Does not apply to H10-76XL series.)
Microphones:
M-7A:
■
Incremental DC and Dynamic AC, 50 Ω
±
20%.
■
Sensitivity: 400 mV
±
6dB into 150 Ω AC load @ 1 KHz for 114dB SPL input.
M-101:
■
Low Impedance Position: 5 Ω nominal, sensitivity .07-.14 mV@ 103 dB SPL
into 5 Ω load @ 1000 Hz.
■
High Impedance Position: 400 mV
±
6 dB @114 dB SPL 1/4”, 1000 Hz bias
8-16 volts behind 470 Ω and with a 150 Ω AC input impedance.
M-87:
■
Microphone designed to be used in aircraft requiring a LOW IMPEDANCE
microphone. Microphone impedance is nominally 5 Ω.
■
Sensitivity: .05 to 11 mV across 5 Ω load at 1000 Hz with an input of
103 dB SPL.
■
Frequency response: 200-6000 Hz
ATTENUATION
