Sampling device having an intrinsic filter

• US 6,265,998 B1
• Filed: 11/30/1999
• Issued: 07/24/2001
• Est. Priority Date: 11/30/1999
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Guardian Corp. (Broadcom, Inc.)
• Inventors: Samori, Carlo, Banu, Mihai
• Primary Examiner(s): Young, Brian
• Assistant Examiner(s): NGUYEN, JOHN B
• Application Number:
  US09/451,044
• Time in Patent Office: 602 Days
• Field of Search: 341/122, 341/123, 341/172, 341/143, 341/111, 341/112, 341/116, 341/155, 341/156, 341/157, 341/113, 341/114, 341/162, 341/181, 341/177, 325/42
• 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 generate the output samples such that at least one aliasing image is removed.

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 de lay 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.