Patent ID: 7894616
Filing Date: 2011-02-22
Classification: H04R

Abstract:
1. A condenser microphone employing a wide band stop filter for wideband signals of low frequency and radio frequency, the condenser microphone having improved resistance to electrostatic discharge applied from outside and preventing radio frequency interference to decrease noise, the condenser microphone comprising: an acoustic module for converting sound pressure into an electric signal; an amplification means for amplifying the electric signal input from the acoustic module; and an EM-noise-filtering/ESD-blocking section for blocking a wideband signal having low frequency and radio frequency output from the amplification means, blocking introduced electromagnetic waves, radio wave noise, and electrostatic discharge, the EM-noise-filtering/ESD-blocking section comprising: wherein the first capacitor has a capacitance of 10 pF, the second capacitor has a capacitance selected from the group consisting of 1 nF, 1.5 nF, 2.2 nF, 3.3 nF, 4.7 nF, 6.8 nF, 10 nF, 15 nF, 22 nF, 33 nF, 47 nF, 68 nF and 100 nF, and the first resistor has a resistance selected from the group consisting of 220Ω, 330Ω, 430Ω, 620Ω, 680Ω, 820Ω and 1 KΩ, and wherein the first bypass capacitor bypasses a low frequency band and the second bypass capacitor bypasses a high frequency band.