> 4.4 | Balanced Microphone Feeding

> Figure 16 shows a balanced feeding circuit for a microphone. The solution of Figure 16 is realized on the DSB75.
> Balanced microphone feeding is recommended if the cable of the final product (for example a GSM desktop telephone) is not shielded and exceeds 10cm.
> Figure 16: Circuit of a balanced microphone and earpiece feeding
> R3, R4, C6 have been chosen to smoothen the feeding voltage. C7 and C10 have been added to suppress the demodulation at the D1 diode. The coupling capacitors C4 and C5 should be at least 100nF. R8…R11 supply the bias voltage for the inputs.