Digital speaker driving apparatus
A digital sound system suitable for a digital speaker device to directly convert analog sound by a circuit using a ΔΣ modulator and a mismatch shaping filter circuit to output a plurality of digital signals and a plurality of speakers driven by the plurality of digital signals. A digital speaker driving device includes a ΔΣ modulator, a post filter, s driving circuits, and a power supply circuit to supply power to the ΔΣ modulator, the post filter and the s driving elements, and the s driving circuits are adapted to s digital signal terminals.
1. A headphone apparatus having a digital signal source from a mobile electronic device comprising:
a digital speaker having s number of digital signal terminals; and
a digital speaker driving apparatus connected to the mobile electronic device and driving the digital speaker including:
a ΔΣ modulator modulating a digital input signal inputted from the mobile electronic device and outputting an n bit digital signal;
a post filter connected to the ΔΣ modulator and outputting an m bit digital signal obtained by miss-match shaping the n bit digital signal; and
s number of driving circuits corresponding to the s number of digital signal terminals, one part of the m bit digital signal being inputted to the s number of driving circuits and the s number of driving circuits outputting a digital signal,
wherein the s numbers of both the digital signal terminals and the driving circuits are less than a number of discrete values represented by a number of bits of the digital input signal inputted from the mobile electronic device.
2. The headphone apparatus according to claim 1 ,
wherein the digital speaker driving apparatus is arranged in the vicinity of a group of coils of the digital speaker.
3. The headphone apparatus according to claim 1 ,
wherein the mobile electronic device is a mobile digital sound source play back apparatus.
4. The headphone apparatus according to claim 1 ,
wherein the mobile electronic device is a mobile phone device.
5. The headphone apparatus according to claim 1 , further comprising:
a power circuit including a battery;
wherein the power circuit supplies a power to the ΔΣ modulator, the post filter and the s number of driving circuits.
6. The headphone apparatus according to claim 1 ,
wherein the ΔΣ modulator, the post filter and the s number of driving circuits are supplied with power from a separate external power source.
7. The headphone apparatus according to claim 1 ,
wherein the digital input signal is inputted from the mobile electronic device via wireless communication.
8. A personal computer comprising:
a digital speaker having s number of digital signal terminals; and
a digital speaker driving apparatus driving the digital speaker including:
a ΔΣ modulator modulating a digital input signal and outputting an n bit digital signal;
a post filter connected to the ΔΣ modulator and outputting an m bit digital signal obtained by miss-match shaping the n bit digital signal; and
s number of driving circuits, one part of the m bit digital signal being inputted to the s number of driving circuits, the s number of driving circuits outputting a digital signal,
wherein the s numbers of both the digital signal terminals and the driving circuits are less than a number of discrete values represented by a number of bits of the digital input signal.
9. The personal computer according to claim 8 ,
wherein the digital speaker driving apparatus is arranged in the vicinity of a group of coils of the digital speaker.