| 摘要 |
A digital amplifier amplifies an input signal from a tuner (107) which receives a broadcast wave of a set reception frequency so as to suppress degradation of the high-band reproduction performance and lowering of the amplification efficiency. The digital amplifier includes: a band division unit (102) for dividing an input signal into a plurality of bands; a high-band pulse width modulation unit (103a) and a low-band pulse width modulation unit (103b) which modulate the input signal of the respective bands divided by the band division unit (102), by the pulse width modulation method; a switching frequency control unit (101) which obtains a reception frequency of the tuner (107) and controls a switching frequency (fsa) in the high-band pulse width modulation unit (103a) and a switching frequency (fsb) in the low-band pulse width modulation unit (103b); and a high-band amplification unit (104a) and a low-band amplification unit (104b) which amplify the input signal which has been subjected to pulse width modulation by the high-band pulse width modulation unit (103a) and the low-band pulse width modulation unit (103b). |
