Analog-to-digital conversion system, correction circuit, and correction method

1. An analog-to-digital conversion system comprising:

a pipelined analog-to-digital conversion circuit for receiving an analog signal and converting the analog signal to a digital signal for output; and

a correction circuit for controlling a correction of a gain error of said analog-to-digital conversion circuit,

said correction circuit including:

a filter for receiving the output signal of said analog-to-digital conversion circuit and extracting a predetermined frequency component generated by a gain error of said analog-to-digital conversion circuit; and

a control circuit for calculating a power of the frequency component extracted by said filter and for generating a control signal for correcting the gain error of said analog-to-digital conversion circuit, based on the frequency component extracted by said filter and supplying the generated control signal to said analog-to-digital conversion circuit.

2. The analog-to-digital conversion system according to claim 1 , wherein said filter comprises a band pass filter.

3. The analog-to-digital conversion system according to claim 1 , wherein said control circuit generates the control signal for correcting the gain error of said analog-to-digital conversion circuit to reduce a value of the power.

4. The analog-to-digital conversion system according to claim 1 , wherein a plurality of said pipelined analog-to-digital conversion circuits are provided in parallel and are driven respectively by sampling clock signals, phases of which are spaced each other.

5. The analog-to-digital conversion system according to claim 1 , wherein said analog-to-digital conversion circuit comprises:

a sample and hold circuit;

a multi-stage (N-stage) pipelined analog-to-digital converter;

a conversion circuit for receiving a digital output of said multi-stage (N-stage) pipelined analog-to-digital converter, converting the digital output from a redundant representation to a non-redundant representation, and outputting the converted result; and

a gain error correction circuit for receiving the output of said conversion circuit and correcting the gain error based on the control signal.

6. The analog-to-digital conversion system according to claim 1 , wherein a band-limited signal is supplied to an analog input terminal of said analog-to-digital conversion circuit;

wherein, in said correction circuit, said filter selectively extracts a signal having a predetermined range of frequency band including a frequency obtained by subtracting a center frequency of the band-limited signal from a Nyquist frequency by letting the signal pass through said filter.

7. The analog-to-digital conversion system according to claim 1 ,

wherein said control circuit comprises;

a power calculation unit for calculating the power of the frequency component extracted by said filter; and

a correction control unit for receiving the power calculated by said power calculation unit, generating the control signal for correcting the gain error of said analog-to-digital conversion circuit to reduce a value of the power, and supplying the control signal to said analog-to-digital conversion circuit.

8. An analog-to-digital conversion system comprising:

a pipelined analog-to-digital conversion circuit for receiving an analog signal and converting the analog signal to a digital signal for output; and

a correction circuit for controlling a correction of a gain error of said analog-to-digital conversion circuit.

said correction circuit including:

a filter for receiving the output signal of said analog-to-digital conversion circuit and extracting a predetermined frequency component generated by a gain error of said analog-to-digital conversion circuit; and

a control circuit for generating a control signal for correcting the gain error of said analog-to-digital conversion circuit, based on the frequency component extracted by said filter and supplying the generated control signal to said analog-to-digital conversion circuit,

wherein a band-limited signal is supplied to an analog input terminal of said analog-to-digital conversion circuit;

wherein, in said correction circuit, said filter selectively extracts a signal having a predetermined range of frequency band including a frequency obtained by subtracting a center frequency of the band-limited signal from a Nyquist frequency by letting the signal pass through said filter; and

wherein said control circuit comprises;

a power calculation unit for calculating a power of the frequency component extracted by said filter; and

a correction control unit for receiving the power calculated by said power calculation unit, generating the control signal for correcting the gain error of said analog-to-digital conversion circuit to reduce a value of the power, and supplying the control signal to said analog-to-digital conversion circuit.

9. An analog-to-digital conversion system comprising:

a plurality of parallel pipelined analog-to-digital conversion circuits, each receiving an analog signal at an analog input terminal thereof, converting the analog signal to a digital signal, and outputting the converted signal, said plurality of analog-to-digital conversion circuits receiving clock signals as sampling clock signals, phases of said clock signals being spaced each other;

a multiplexer for receiving and multiplexing a plurality of digital signal outputs from said plurality of analog-to-digital conversion circuits;

a band pass filter for receiving the output signal of said multiplexer and extracting a predetermined frequency component generated by a gain error of said analog-to-digital conversion circuits;

a power calculation unit for calculating a power of the frequency component extracted by said band pass filter; and

a correction circuit control unit for supplying control signals to said plurality of analog-to-digital conversion circuits for correcting the gain error of said analog-to-digital conversion circuits to reduce a value of the power of the frequency component.

10. A correction circuit for correcting a gain error of a pipelined analog-to-digital conversion circuit that receives an analog signal, converts the analog signal to a digital signal, and outputs the converted signal, said correction circuit comprising:

a filter for receiving the output signal of said analog-to-digital conversion circuit and extracting a frequency component generated by a gain error of said analog-to-digital conversion circuit; and

a control circuit for calculating a power of the frequency component extracted by said filter and outputs a control signal for correcting the gain error of said analog-to-digital conversion circuit to reduce a value of the power.

11. A correction method for a pipelined analog-to-digital conversion circuit that receives an analog signal, converts the analog signal to a digital signal, and outputs the converted signal, said correction method comprising:

receiving the output signal of said analog-to-digital conversion circuit and extracting a frequency component, generated by a gain error of said analog-to-digital conversion circuit by a filter;

correcting the gain error of said analog-to-digital conversion circuit based on the frequency component extracted by said filter; and

calculating a power of the frequency component extracted by said filter.

12. The correction method for an analog-to-digital conversion circuit according to claim 11 , wherein said filter comprises a band pass filter.

13. The correction method for an analog-to-digital conversion circuit according to claim 11 , further comprising:

correcting the gain error of said analog-to-digital conversion circuit to reduce a value of the power of the extracted frequency component.

14. The correction method for an analog-to-digital conversion circuit according to claim 11 , wherein a plurality of said pipelined analog-to-digital conversion circuits are provided in parallel and are driven by sampling clock signals, phases of which are spaced each other.

15. A correction method for a pipelined analog-to-digital conversion circuit that receives an analog signal, converts the analog signal to a digital signal, and outputs the converted signal, said correction method comprising:

receiving the output signal of said analog-to-digital conversion circuit and extracting a frequency component, generated by a gain error of said analog-to-digital conversion circuit by a filter;

correcting the gain error of said analog-to-digital conversion circuit based on the frequency component extracted by said filter;

receiving a band-limited signal at an analog input terminal of said analog-to-digital conversion circuit;

selectively letting a signal pass through said filter, said signal having a predetermined range of frequency band including a frequency obtained by subtracting a center frequency of the band-limited signal from a Nyquist frequency,

calculating a power of a frequency component output by said filter; and

generating a control signal for correcting the gain error of said analog-to-digital conversion circuit to reduce the calculated power.

16. The correction method for an analog-to-digital conversion circuit according to claim 15 , wherein said analog-to-digital conversion circuit comprises:

a sample and hold circuit;

a multi-stage (N-stage) pipelined analog-to-digital converter;

a conversion circuit that receives an output of said multi-stage (N-stage) pipelined stage analog-to-digital converter, converts the output from a redundant representation to a non-redundant representation, and outputs the converted result; and

a gain error correction circuit that receives the output signal of said conversion circuit and corrects the gain error based on the control signal.

17. The correction method for an analog-to-digital conversion circuit according to claim 16 , wherein there are provided at least two said analog-to-digital conversion circuits, said correction method further comprising:

(a) correcting a gain error of the sample and hold circuit of one said analog-to-digital conversion circuit; and

(b) correcting a gain error of pipeline stages, from a first to a Nth pipeline stages of said analog-to-digital conversion circuit for two said analog-to-digital conversion circuits, alternately.

18. The correction method for an analog-to-digital conversion circuit according to claim 17 , wherein said step (a) comprises:

(a1) updating the gain error of the sample and hold circuit of one said analog-to-digital conversion circuit from a current value to a first value, to which a predetermined amount is added in advance, and calculating a power (referred to as a “first power”) of the frequency component extracted by said filter, said power corresponding to the gain error of the first value of one said analog-to-digital conversion circuit;

(a2) updating the gain error of the sample and hold circuit of one said analog-to-digital conversion circuit from a current value to a second value, from which a predetermined amount is subtracted in advance, and calculating a power (referred to a “second power”) of the frequency component extracted by said filter, said power corresponding to the gain error of the second value of one said analog-to-digital conversion circuit; and

(a3) repeating said (a1) and (a2) until an absolute value of a difference between the first power and the second power becomes smaller than a predetermined threshold value defined in advance or until a predetermined repetition count defined in advance is reached.

19. An analog-to-digital conversion system comprising:

analog-to-digital conversion means for receiving an analog signal and converting the analog signal to a digital signal for output; and

correction means for controlling a correction of a gain error of said analog-to-digital conversion circuit,

said correction means including:

filter means for receiving the output signal of said analog-to-digital conversion means and extracting a predetermined frequency component generated by a gain error of said analog-to-digital conversion means; and

control means for generating a control signal for correcting the gain error of said analog-to-digital conversion means, based on the frequency component extracted by said filter means and supplying the generated control signal to said analog-to-digital conversion means.

20. The analog-to-digital conversion system according to claim 19 , wherein said control means calculates a power of the frequency component extracted by said filter means and generates the control signal for correcting the gain error of said analog-to-digital conversion means to reduce a value of the power.