Sampling device having an intrinsic filter

• US 20010002123A1
• Filed: 01/08/2001
• Published: 05/31/2001
• Est. Priority Date: 11/30/1999
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Carlo Samori, Mihai Banu
• Inventors: Samori, Carlo, Banu, Mihai
• Granted Patent: US 6,473,014 B2
• Time in Patent Office: Days
• US Class Current: 341/122
• CPC Class Codes: H03H 17/0219 Compensation of undesirable effects, e.g. quantisation noise, overflow stability problems H03H17/0461
• CPC Class Codes: H03H 17/0273 Polyphase filters

Abstract

A sampling device for sampling an input signal having intrinsic filter properties. The sampling device samples a continuous analog input signal according to a sampling signal. The sampling device includes a first sampling switch for sampling the input signal, in response to a sampling signal, to create a first set of samples. Furthermore, the sampling device incorporates a time delay device for time delaying the first set of samples. The sampling device also includes a phase shift device for phase shifting the input signal. The phase delayed input signal is then fed into a second sampling switch for sampling in response to the sampling signal to create a second set of samples. Further, a summer is incorporated to sum the first set of samples with the second set of samples to create the output samples.

Claims

1. A sampling device for sampling an input signal to generate output samples, the sampling device comprising:

a first sampling switch for sampling the input signal in response to a sampling signal to create a first set of samples;

a time delay device for time delaying the first set of samples;

a phase shift device for phase shifting the input signal;

a second sampling switch for sampling the phase shifted input signal in response to the sampling signal to create a second set of samples; and

a summer for summing the first and the second set of samples to create the output samples.

2. The sampling device of

claim 1

, wherein the time delay device provides a first predetermined time delay, and the phase shift device provides a first predetermined phase shift.

3. The sampling device of

claim 2

, wherein the first predetermined time delay corresponds with the first predetermined phase shift.

4. The sampling device of

claim 3

, wherein the first predetermined phase shift is −

π

/2 radians.

5. The sampling device of

claim 3

, wherein the first predetermined time corresponds with one sampling period of the sampling signal.

6. The sampling device of

claim 1

, wherein the input signal is fed into a mixer having a first and a second mixed output, the second mixed output being out of phase with the first mixed output by −

π

/2 radians.

7. The sampling device of

claim 2

, further comprising:

a second phase shift device for phase shifting the input signal according to a second predetermined phase shift;

a third sampling switch for sampling the input signal as shifted by the second predetermined phase shift;

a second time delay device for time delaying the sampled phase shifted input signal shifted by the second predetermined phase shift according to a second predetermined time delay to create a third set of samples, such that the summer sums the first, second and third samples to create the output samples.

8. The sampling device of

claim 7

, further comprising at least one amplifier for amplifying the time delayed sampled shifted input signal, the at least one amplifier having a gain.

9. The sampling device of

claim 8

, wherein the gain is −

2.

10. The sampling device of

claim 7

, wherein the second predetermined time delay corresponds with the second predetermined phase shift.

11. The sampling device of

claim 10

, wherein the second predetermined phase shift is −

π

radians.

12. The sampling device of

claim 10

, wherein the second predetermined time corresponds with two sampling periods of the sampling signal.

13. An analog to digital converter for converting an analog input signal into a digital output signal, the analog to digital converter comprising:

a sampling device for sampling the analog input signal and creating output samples, the sampling device comprising;

a number of branches, j, where j is a whole number greater than one, each branch comprising;

a phase shift device for phase shifting the input signal, the phase shift device having a phase shift coefficient;

a sampling switch for sampling the phase shifted input signal in response to a sampling signal to create a set of samples;

a time delay device for time delaying the set of samples, the time delay device having a time delay coefficient; and

an amplifier for amplifying the time delayed set of samples, the amplifier having a gain coefficient, wherein the phase delay coefficient comprises the difference between j and k, where k is a whole number between one and j, and the time delay and gain coefficients correspond with the terms of a Z transform;

a summer for summing the amplified timed delayed set of samples from each branch to generate the output samples; and

a holding device for holding the output samples;

a quantizing device for quantizing the output samples; and

an encoding device for encoding the quantized output samples.

14. The analog to digital converter of

claim 13

, wherein the time delay device of each branch provides a predetermined time delay multiplied by the time delay coefficient of the respective branch, and the phase shift device provides a predetermined phase shift multiplied by the phase shift coefficient of the respective branch.

15. The analog to digital converter of

claim 14

, wherein the predetermined phase shift is −

π

/2 radians.

16. The analog to digital converter of

claim 14

, wherein the predetermined time corresponds with one sampling period of the sampling signal.

17. The analog to digital converter of

claim 13

, wherein the phase shift device comprises a mixer for generating at least two mixed outputs which are out of phase with each other by −

π

/2 radians.

18. An electronic device for receiving an input radio frequency (“

RF”

) signal, and generating a digital signal, the electronic device comprising;

an RF filter for filtering the input RF signal;

an amplifier for amplifying the filtered input RF signal;

an RF mixer having an RF oscillator for mixing the amplified filtered input RF signal;

an intermediate frequency (“

IF”

) filter for filtering the RF mixed, amplified and filtered input RF signal; and

an analog to digital converter for converting the filtered, RF mixed, amplified and filtered input RF signal into a digital signal, the analog to digital converter comprising;

a sampling device for sampling the filtered, RF mixed, amplified and filtered input RF signal and creating output samples, the sampling device comprising;

a first sampling switch for sampling the filtered, RF mixed, amplified and filtered input RF signal in response to a sampling signal to create a first set of samples;

a time delay device for time delaying the first set of samples;

a phase shift device for phase shifting the filtered, RF mixed, amplified and filtered input RF signal;

a second sampling switch for sampling the phase shifted, filtered, RF mixed, amplified and filtered input RF signal in response to the sampling signal to create a second set of samples; and

a summer for summing the first and second set of samples to generate the output samples; and

a holding device for holding the output samples;

a quantizing device for quantizing the output samples; and

an encoding device for encoding the quantized output samples to create the digital signal.

19. The electronic device of

claim 18

, wherein the time delay device provides a first time delay of one sampling period of the sampling signal, and the phase shift device provides a first phase shift of −

π

/2 radians.

20. The electronic device of

claim 18

, wherein the filtered, RF mixed, amplified and filtered input RF signal is fed into a mixer having a first and a second mixed output, the second mixed output being out of phase with the first mixed output by −

π

/2 radians.

21. The electronic device of

claim 18

, further comprising:

a second phase shift device for phase shifting the filtered, RF mixed, amplified and filtered input RF signal by −

π

radians;

a third sampling switch for sampling the filtered, RF mixed, amplified and filtered input RF signal phase shifted by −

π

radians; and

a second time delay device for time delaying the sampled phase shifted input signal shifted by two sampling periods of the sampling signal to create a third set of samples, such that the summer sums the first, second and third samples to create the output samples.

22. The electronic device of

claim 21

, further comprising an amplifier for amplifying the third set of samples, the amplifier having a gain of −

2.