The input circuit common mode noise suppression microphone amplifier with balance |
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- Microphone Circuits / Audio Circuits
Because the common mode signal rejection ratio depends on the input transformer, it should be used or homemade good balance transformer (It should be noted l frequency increase
s, the balance will fall), is determined to consider the transmission frequency range boost ratio. Step-up ratio is primary to secondary turns ratio. Terminal can also be used to represent the square root of the impedance ratio. The circuit uses a utility available on the market THS-2 transformer impedance ratio of 6000: iookQ, so the boost ratio:/1 xo Lily F4, this kind available 12dB voltage gain from the input conversion noise this point look relatively favorable. Resistance R, and in the sub-Yi across the transformer, it seems no need to use iokfl, but the frequency characteristics of the transformer with a resistance value becomes, so the frequency characteristics measured to determine a post- chu t, cl high noise suppression is a low-pass filter for high inhibition effect depends dry cl, Zhang Rz available plus the equivalent output resistance is obtained. OP zoom uses a closed-loop frequency characteristics of a good low-noise type OP37, straight surprised coupling. If you use a high OP amplifier offset voltage, should the series with a roar of dozens of micro-ho capacitance mouth
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