降低串扰的DirectPath耳机放大器

　　Figure 1 is commonly used in most mobile phones and tablets. The headphone cable is also used as an FM antenna.

　　The amplifier sets a bias output signal riding on the voltage sensed by the sense pin. With this technique and Kirchhoff’s current law， Figure 1 is analyzed. Assume a sine wave signal is applied to only on the HP （Head Phone） left output. The current that returns to ground during positive sine wave cycle causes a voltage drop across the nH coil. Thus， the sense pin has some voltage sensed instead of clean ground potential of 0V. The HP amplifier right output contains this small signal. Thus， a right ear headphone load that is connected to the jack has both terminals swinging simultaneously causing the potential difference to be zero， and hence， no audible output - no crosstalk. The same is true when the signal is playing only on the HP right channel.