Integrated digital volume potentiometer circuit

Figure 4-18 is a volume and tone control circuit composed of a volume potentiometer T (Xi153AP) and a tone potentiometer T (∞155AP)
. In the circuit, Rx and cx are clock oscillation components, and their values ​​can be selected according to the required oscillation frequency. : f (FiC=l/
0.7 xCx (Hz). Among them, Rs≥3Rxo
    Guardian》153AP adopts a two-level attenuation adjustment method. The total attenuation adjustment range is 0-66dB, and the step unit attenuation
is 2dBo. One of the first-level attenuation adopts The unit attenuation of 10dB (corresponding to a resistance value of 50 kfl, i.e. RATT1); the second level attenuation
adopts a unit attenuation of 2dB (corresponding to a resistance value of 20kfl, i.e. RATT2). There are two sets of the same circuits in the lc, which are
supplied separately. Left and right channels are used. In order to obtain a good signal-to-noise ratio, RArTl can be used for the input terminal and RATI2 for the output terminal.
    TC9155AP is equipped with two sets of identical circuits. Each set of adjustment range is -6~ +6dB, and the resistance value It is 100kn, divided into
1 to 3 steps for adjustment, and one set is used for each of the two channels. The resistance network of the electronic potentiometer
and the external capacitor are jointly connected in the feedback loop of the operational amplifier to form a feedback tone control circuit. Operational amplifier Using TA75558P,
MC1458 or other similar operational amplifier circuits can also be used .