Sample rate converter

A digital communication system, comprising:

• a signal transmission channel;
• a transmitter, the transmitter transmitting a signal to the channel;
• a receiver, the receiver receiving an analog signal from the channel and converting the analog signal approximately to the signal transmitted from the transmitter;
• wherein the receiver includes an A/D (analog-to-digital) converter for converting the analog signal to a first digital signal, and a D/D (digital-to-digital) converter for converting the first digital signal into a second digital signal, the D/D converter comprises:
• a converter filter, the converter filter receiving a first clock and receiving the first digital signal which is sampled at the first clock and outputting the second digital signal sampled at a second clock, the converter filter receiving a phase control signal which controls conversion from the first digital signal to the second digital signal;
• and
• a timer, the timer receiving the second clock and a baud rate of the analog signal and generating the first clock and the phase control signal for the converter filter, the timer comprising an accumulator which accumulates the baud rate at each tick of the second clock, and an overflow signal of the accumulator generates the first clock.

A converter for converting a first digital signal representing an analog signal into a second digital signal representing the analog signal, comprising:

• a converter filter, the converter filter receiving the first digital signal which is sampled at a first clock and outputting the second digital signal sampled at a second clock, the converter filter receiving a phase control signal which controls conversion from the first digital signal to the second digital signal;
• and
• a timer, the timer receiving the second clock and a baud rate of the analog signal and generating the first clock and the phase control signal for the converter filter, the timer comprising:
• an accumulator which accumulates the baud rate at each tick of the second clock, and an overflow signal of the accumulator which generates the first clock;
• and
• a phase calculator which calculates a phase between the first and second clock, the phase of the phase calculator generates the phase control signal.

A resampling system in a digital communication system for converting a first digital signal representing an analog signal into a second digital signal representing the analog signal, comprising:

• a converter filter, the converter filter receiving the first digital signal which is sampled at a first clock and outputting the second digital signal sampled at a second clock, the converter filter receiving a phase control signal which controls conversion from the first digital signal to the second digital signal;
• and
• a timer, the timer receiving the second clock and a baud rate of the analog signal and generating the first clock and the phase control signal for the converter filter.
• wherein the timer is made of a numerical controlled oscillator, the timer comprising:
• an accumulator which accumulates the baud rate at each tick of the second clock, and an overflow signal of the accumulator which generates the first clock;
• and
• a phase calculator which calculates a phase between the first and second clock, the phase of the phase calculator generates the phase control signal.

A resampling system in a digital communication system for converting a first digital signal representing an analog signal into a second digital signal representing the analog signal, comprising:

• a converter filter, the converter filter receiving the first digital signal which is sampled at a first clock and outputting the second digital signal sampled at a second clock, the converter filter receiving a phase control signal which controls conversion from the first digital signal to the second digital signal;
• and
• a timer, the timer receiving the second clock and a baud rate of the analog signal and generating the first clock and the phase control signal for the converter filter,
• wherein the timer is made of a numerical controlled oscillator, the timer comprising a phase calculator which calculates a phase between the first and second clock, and the phase of the phase calculator generates the phase control signal.

A digital communication system, comprising:

• a signal transmission channel;
• a transmitter, the transmitter transmitting a signal to the channel;
• a receiver, the receiver receiving an analog signal from the channel and converting the analog signal approximately to the signal transmitted from the transmitter;
• wherein the receiver includes an A/D (analog-to-digital) converter for converting the analog signal to a first digital signal, and a D/D (digital-to-digital) converter for converting the first digital signal into a second digital signal, the D/D converter comprises:
• a converter filter, the converter filter receiving the first digital signal which is sampled at a first clock and outputting the second digital signal sampled at a second clock, the converter filter receiving a phase control signal which controls conversion from the first digital signal to the second digital signal;
• and
• a timer, the timer being made of a numerical controlled oscillator and receiving the second clock and a baud rate of the analog signal, and generating the first clock and the phase control signal for the converter filter, the timer comprising:
• an accumulator which accumulates the baud rate at each tick of the second clock, and an overflow signal of the accumulator which generates the first clock;
• and
• a phase calculator which calculates a phase between the first and second clock, and the phase of the phase calculator generates the phase control signal.