Method and system for VCO-based analog-to-digital conversion (ADC)

• US 6,809,676 B1
• Filed: 08/20/2002
• Issued: 10/26/2004
• Est. Priority Date: 08/20/2002
• Status: Expired due to Term

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Inventors: Younis, Ahmed, Robinson, Moises E., Hassoun, Marwan M.
• Primary Examiner(s): WAMSLEY, PATRICK G
• Application Number:
  US10/224,977
• Time in Patent Office: 798 Days
• Field of Search: 341/139, 341/142, 341/157, 341/161, 341/152, 341/166, 375/148, 375/316, 375/375, 375/376
• US Class Current: 341/157
• CPC Class Codes: H03M 1/60 with intermediate conversion to frequency of pulses

Abstract

A VCO (110) can be configured to convert an analog input signal (105) to a digital output signal (125). In accordance with the inventive arrangements, the VCO can convert the analog input signal to at least one intermediate signal (130) having a frequency dependent on the analog input signal. A frequency detector (115) can be configured to determine a frequency of at least one intermediate signal. Subsequently, a mapping circuit (120) can be configured to map the determined frequency of the at least one intermediate signal to an output value representing the digital output signal (125).

Claims

1. A method for converting an analog input signal to a digital output signal, the method comprising:

converting the analog input signal to at least one intermediate signal having a frequency dependent on the analog input signal regardless of polarity;

determining said frequency of said at least one intermediate signal; and

mapping said determined frequency of said at least one intermediate signal to an output value, said output value representing the digital output signal representative of the converted analog input signal.

2. The method according to claim 1, wherein said converting step further comprises converting a voltage of the analog input signal to said intermediate signal.

3. The method according to claim 2, further comprising controlling a linearity of the digital output signal by controlling said conversion of said voltage of said analog input signal to said intermediate signal.

4. The method according to claim 1, further comprising controlling a resolution of the digital output signal by controlling said determination of said frequency of said at least one intermediate signal.

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

a voltage controlled oscillator for converting the analog input signal to at least one intermediate signal having a frequency dependent on the analog input signal regardless of polarity;

at least one frequency detector for determining said frequency of said at least one intermediate signal; and

a mapping circuit for mapping said frequency of said at least one intermediate signal to an output value, said output value representing the digital output signal representative of the converted analog input signal.

6. The analog-to-digital converter according to claim 5, wherein said voltage controlled oscillator further comprises means for converting a voltage of the analog input signal to said intermediate signal.

7. The analog-to-digital converter according to claim 6, wherein said voltage controlled oscillator further comprises means for controlling a linearity of the analog-to-digital converter.

8. The analog-to-digital converter according to claim 5, wherein said frequency detector further comprises means for controlling a resolution of the analog-to-digital converter.

9. The analog-to-digital converter according to claim 5, wherein the at least one frequency detector and the mapping circuit are embodied in a digital signal processor.

10. The analog-to-digital converter according to claim 5, wherein the mapping circuit is implemented using a lookup table.

11. The analog-to-digital converter according to claim 5, wherein the mapping circuit is implemented using an algorithmic calculation.

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

a voltage controlled oscillator for converting the analog input signal to at least one intermediate signal having a frequency dependent on the analog input signal regardless of polarity; and

a processor for determining said frequency of said at least one intermediate signal and mapping said frequency of said at least one intermediate signal to an output value, said output value representing the digital output signal representative of the converted analog input signal.

13. The analog-to-digital converter according to claim 12, wherein said voltage controlled oscillator further comprises means for converting a voltage of the analog input signal to said intermediate signal.

14. The analog-to-digital converter according to claim 13, wherein said voltage controlled oscillator further comprises means for controlling a linearity of the analog-to-digital converter.

15. The analog-to-digital converter according to claim 12, wherein said frequency detector further comprises means for controlling a resolution of the analog-to-digital converter.

16. The analog-to-digital converter according to claim 12, wherein the processor is a digital signal processor.

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

means for converting the analog input signal to at least one intermediate signal having a frequency dependent on the analog input signal regardless of polarity; and

means for determining said frequency of said at least one intermediate signal and mapping said frequency of said at least one intermediate signal to an output value, said output value representing the digital output signal representative of the converted analog input signal.

18. The analog-to-digital converter of claim 17, wherein the means for converting the analog input signal comprises an automatic gain control circuit.