 |
|
|
|
|
|
 Title: |
US4862169:
Oversampled A/D converter using filtered, cascaded noise shaping modulators
[ Derwent Title ]
|
| Country: |
US United States of America
|
| |
| Inventor: |
van Bavel, Nicholas R.; Austin, TX
Williams, Tim A.; Austin, TX
|
| Assignee: |
Motorola, Inc., Schaumburg, IL
other patents from MOTOROLA, INC. (386735) (approx. 18,357)
News, Profiles, Stocks and More about this company
|
| Published / Filed: |
1989-08-29
/ 1988-03-25
|
| Application Number: |
US1988000172823
|
| IPC Code: |
Advanced:
H03M 3/02;
Core:
more...
IPC-7:
H03M 3/02;
|
| U.S. Class: |
Current:
341/143;
375/252;
Original:
341/143;
375/033;
|
| Field of Search: |
341/143,155,162,163
381/033
375/026,33
|
| Priority Number: |
| 1988-03-25 |
US1988000172823 |
|
| Abstract: |
An oversampling A/D converter for high resolution data conversion is provided. An analog input signal is quantized into a digital equivalent value with a finite quantization error associated therewith in a first circuit portion. An analog low pass filter is inserted between the first circuit portion and a second circuit portion similar in function and circuitry to the first circuit portion. The second circuit portion functions to remove the error of the first circuit portion from an output signal by providing a signal component, which when added with the output of the first circuit portion cancels the error of the first circuit portion. The low pass filter provides attenuation of quantization error provided by the second circuit portion which results in an output signal with a significantly attenuated error.
|
| Attorney, Agent or Firm: |
King, Robert L. ;
|
| Primary / Asst. Examiners: |
Shoop, Jr., William M.; Hoff, Marc S.
|
| INPADOC Legal Status: |
Show legal status actions
|
| Family: |
None
|
First Claim:
Show all 11 claims |
We claim:
1. An oversampling A/D converter operating at a sampling frequency higher than an input signal frequency and having an input for receiving an analog input signal and an output for providing an equivalent digital output signal, comprising: first and second quantization loops, each quantization loop comprising:
- means for integrating a difference between an input terminal signal and a feedback signal;
- a quantizer for quantizing an output from the integrator and providing a loop output signal; and
- feedback means having an input coupled to the loop output signal and an output for providing the feedback signal;
- first filter means having an input coupled to a first loop output signal of a first quantization loop, for filtering the first loop output signal by a first transfer function to provide a first filter signal;
- second filter means having an input coupled to the output of the integrator of the first loop, and an output, said second filter means filtering the output of the integrator of the first loop by a second transfer function to provide the input terminal signal for the second quantization loop;
- gain means having an input coupled to the output of the second filter means, for amplifying the input terminal signal for the second quantization loop; and
- output means having an input coupled to the loop output signal of the second quantization loop for attenuating the loop output signal of the second quantization loop.
|
| Background / Summary: |
Show background / summary
|
| Drawing Descriptions: |
Show drawing descriptions
|
| Description: |
Show description
|
| Forward References: |
Show 26 U.S. patent(s) that reference this one
|
