Power source apparatus

Claim 2

A power source apparatus for use in a digital audio recording apparatus, the digital audio recording apparatus including a variable speed drive being driven by an external sampling dock signal having a frequency used in digital audio equipment, wherein the speed of the drive varies in accordance with the external sampling clock signal, the power source apparatus comprising: a DC power source; a switching arrangement coupled to the DC power source for switching at a variable switching frequency to provide a DC output signal; clock means for providing a clock signal substantially at the external sampling clock frequency; and a controller, responsive to the clock signal having the external sampling clock frequency, for controlling the switching frequency of the switching arrangement to be about an integer multiple of the external sampling clock frequency.

Claim 3

The power source apparatus as defined in claim 1, wherein the switching arrangement includes chopping means for chopping an output from the DC power source to control the DC output signal.

Claim 4

The power source apparatus as defined in claim 1, wherein the switching arrangement includes first converting means for converting an output from the DC power source to an AC signal, and second converting means for converting the AC signal to the DC output signal.

Claim 5

The power source apparatus as defined in claim 1, wherein the controller includes signal generating means for generating a switching signal having a frequency which is about the integer multiple of the external sampling clock frequency, and means for applying the switching signal to the switching arrangement.

Claim 6

The power source apparatus as defined in claim 4, further comprising reference signal generating means for providing a reference signal and comparing means for comparing the reference signal with the DC output signal to provide an error signal, wherein the controller includes means for pulse width modulating the switching signal in accordance with the error signal.

Claim 7

A power source apparatus for use in a digital audio recording apparatus, the digital audio recording apparatus including a variable speed drive mechanism being driven by a dock frequency which is variable in accordance with a sampling frequency in an external audio system, wherein the speed of the drive mechanism varies in accordance with the sampling frequency, the power source apparatus comprising: a DC power source; a DC to AC inverter coupled to the DC power source and having a pair of switching transistors; an AC to DC rectifier coupled to the DC to AC inverter and providing a DC output signal; and clock means for providing a clock signal for switching the pair of switching transistors at a frequency which is about an integer multiple of the sampling frequency.

Claim 8

A power source apparatus for use in a digital audio recording apparatus, the digital audio recording apparatus including a variable speed drive mechanism being driven by a dock frequency which is variable in accordance with a sampling frequency in an external audio system, wherein the speed of the drive mechanism varies in accordance with the sampling frequency, the power source apparatus comprising: a DC power source; a DC to AC inverter coupled to the DC power source and having a pair of switching transistors; an AC to DC rectifier coupled to the DC to AC inverter and providing a DC output signal; and clock means for providing a clock signal for switching the pair of switching transistors at a frequency which is about an integer multiple of the sampling frequency.

Claim 9

The power source apparatus as defined in claim 6, wherein the clock means includes a phase locked loop for generating a pulse train having a frequency which is about the integer multiple of the sampling frequency.

Claim 10

The power source apparatus as defined in claim 7, further comprising: voltage supply means for providing a reference voltage; and error voltage generating means for generating an error voltage in accordance with a difference between the reference voltage and the voltage of the DC output signal, wherein the clock means includes a pulse width modulator for pulse width modulating the pulse train in accordance with the error voltage.

Claim 11

The power source apparatus as defined in claim 8, wherein the clock means includes shaping means coupled to the phase locked loop for shaping the pulse train to produce a sawtooth waveform.

Claim 12

A digital audio system comprising: a digital audio recording apparatus including a variable speed drive being driven by an external sampling clock signal having a frequency used in digital audio equipment, wherein the speed of the drive varies in accordance with the external sampling clock signal; and a power source apparatus, said power source apparatus including: a DC power source; a switching arrangement coupled to the DC power source for switching at a variable switching frequency to provide a DC output signal; clock means for providing a clock signal substantially at the external sampling clock frequency; and a controller, responsive to the clock signal having the external sampling clock frequency, for controlling the switching frequency of the switching arrangement to be an integer multiple of the external sampling dock frequency, thereby preventing the switching frequency of the switching arrangement from causing the generation of noise in the audio frequency range.

Claim 13

A digital audio system comprising: a digital audio recording apparatus including a variable speed drive being driven by an external sampling clock signal having a frequency used in digital audio equipment, wherein the speed of the drive varies in accordance with the external sampling clock signal; and a power source apparatus, said power source apparatus including: a DC power source; a switching arrangement coupled to the DC power source for switching at a variable switching frequency to provide a DC output signal; clock means for providing a clock signal substantially at the external sampling clock frequency; and a controller, responsive to the clock signal having the external sampling clock frequency, for controlling the switching frequency of the switching arrangement to be an integer multiple of the external sampling dock frequency, thereby preventing the switching frequency of the switching arrangement from causing the generation of noise in the audio frequency range.