The input circuit common mode noise suppression microphone amplifier with balance |
|
|
Posted on Mar 28, 2007 4516
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
characters left: