Wide bandwidth analog-to-digital converter and method

• US 4,968,986 A
• Filed: 10/06/1988
• Issued: 11/06/1990
• Est. Priority Date: 10/06/1988
• Status: Expired due to Fees

• Current Assignee: Ideas Incorporated Columbia MD
• Original Assignee: Ideas Limited
• Inventors: Wagner, T. C. Gordon
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Logan, Sharon D.
• Application Number:
  US07/254,034
• Time in Patent Office: 761 Days
• Field of Search: 341/111, 341/155
• US Class Current: 341/111
• CPC Class Codes: H03M 1/1215 using time-division multiplexing

Abstract

A wide bandwidth analog-to-digital converter and method. The input analog signal is supplied to a plurality (N) of parallel channels, each of which includes a modulator for modulating the incoming analog signal in each channel with a different time phased sampling signal. A filter having bandwidths which reject the sum product of the modulator and all frequencies above a predetermined level and passes the filtered signal directly to an analog-to-digital converter and a sampling signal supplied to these converters are at a rate which is predetermined fraction (depending on the number of channels) of the normal rate.

Claims

1. A wide bandwidth analog-to-digital apparatus comprising:

input means for receiving an analog signal to be converted,

N number of parallel channels, each channel including;

means for connecting the channel to said input means,

a modulator,

a filter means connected to said modulator,

an analog to digital converter operated at a rate of 1/N,

means connecting the signal from said filter means to said analog-to-digital converter,

a source of modulating signals for supplying modulating signals to each of said modulators in a phase displaced relation, respectively, said filter means having a bandwidth which rejects the sum products of said analog signal and said modulating signals, and

a source of sampling signals for supplying synchronized sampling signals in said phase displaced relation to respective ones of said analog-to-digital converters.

2. The wide bandwidth analog-to-digital apparatus defined in claim 1, wherein said modulating signals are squarewaves.

3. The wide bandwidth analog-to-digital apparatus defined in claim 1 including a common clock signal source and wherein said source of modulating signals and said source of sampling signals are connected to said common clock signal source.

4. A wide bandwidth analog-to-digital signal apparatus comprising:

input means for receiving a wide bandwidth analog signal to be converted to a digital signal,

a plurality (N) of parallel channels, each channel including;

(a) an analog signal modulator having as one input said wide bandwidth analog signal and as a second input, a modulating signal,

(b) a filter having a predetermined bandwidth connected to said modulator,

(c) an analog-to-digital converter connected to said filter operated at a sampling rate of 1/N, and

a source of modulating signals for supplying a modulating signal to each of said modulators in phased displaced relation relative to each other, there being N phases of modulating signals, one phase for each channel, respectively, and a source of sampling signals for supplying synchronized sampling signals in phase displaced relation to respective ones of said analog-to-digital converters, there being N phases of sampling signals, one phase for each analog-to-digital converter, respectively.

5. The analog-to-digital apparatus defined in claim 4 wherein said modulating signals are square waves.

6. The wide bandwidth analog-to-digital apparatus defined in claim 4 including a common clock signal source and wherein said source of modulating signals and said source of sampling signals are connected to said common clock signal source.

7. A method of converting wide bandwidth analog signal to digital signal comprising:

receiving an analog signal to be converted,

providing N number of parallel channels, each channel including a modulator connected to a filter, which, in turn, is connected to an analog-to-digital converter operated at a rate of 1/N,

supplying modulating signals to each of said modulators in phase displaced relation, there being N phases of modulating signals, one phase for each channel, respectively, and

providing sampling signals for supplying synchronized sampling signals in phase displaced relation to respective ones of said analog-to-digital converters, there being N phases of sampling signals, one phase for each analog-to-digital converter, respectively.

8. The method defined in claim 7 wherein said modulating signals are square waves.