US5374860A
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Multi-tap digital delay line
Assignee: National Semiconductor Corp
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Filing: 1993-01-15
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Granted: 1994-12-20
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Expires: 2013-01-15
Abstract
Abstract A programmable digital delay line having N delay elements, two multiplexers connected to the output of the delay elements, and a comparator connected to the outputs of the multiplexers is disclosed. The invention teaches an apparatus and a method of delaying a signal, while reducing the number of delay elements and the number of connections to multiplexers. In a first embodiment of the invention, the delay elements are inverters or differential delay elements. In a second embodiment, the delay elements are differential delay elements.
Inventors
- 👤 William D. Llewellyn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:24
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/13; H03K5/131; H03K5/133; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/085
Claims Analysis
Total Claims: 62
Claim 1
Independent Claim
194 words
An apparatus for delaying an input signal comprising: a first delay element for producing a first delayed signal, said first delayed element having at least a first input for receiving a first input signal and at least a first output, said first delayed signal being a first representation of said first input signal delayed by a first period; a second delay element for producing a second delayed signal, said second delay element having at least a second input for receiving said first delayed signal and at least a second output, said second delayed signal being a second representation of said first delayed signal delayed by a second period, and said second input of said second delay element being coupled to said first output of said first delay element; and a comparator for comparing said first and second delayed signal to produce an output signal, said comparator having a third and a fourth input and an output, said third input being coupled to said first output and said fourth input being coupled to said second output, said output signal being said input signal delayed by a third period plus any delay caused by said comparator.
Claim 2
Independent Claim
194 words
An apparatus for delaying an input signal comprising: a first delay element for producing a first delayed signal, said first delayed element having at least a first input for receiving a first input signal and at least a first output, said first delayed signal being a first representation of said first input signal delayed by a first period; a second delay element for producing a second delayed signal, said second delay element having at least a second input for receiving said first delayed signal and at least a second output, said second delayed signal being a second representation of said first delayed signal delayed by a second period, and said second input of said second delay element being coupled to said first output of said first delay element; and a comparator for comparing said first and second delayed signal to produce an output signal, said comparator having a third and a fourth input and an output, said third input being coupled to said first output and said fourth input being coupled to said second output, said output signal being said input signal delayed by a third period plus any delay caused by said comparator.
Claim 3
Dependent Claim
16 words
An apparatus as set forth in claim 1 wherein said first and second representations are inversion.
Claim 4
Dependent Claim
24 words
An apparatus as set forth in claim 1 wherein said third input is a positive input and said fourth input is a negative input.
Claim 5
Dependent Claim
24 words
An apparatus as set forth in claim 1 wherein said third input is a negative input and said fourth input is a positive input.
Claim 6
Dependent Claim
45 words
Apparatus of claim 1 further comprising: a first multiplexer coupled between said first input and said third input for programmably selecting said first input signal; and a second multiplexer coupled between said second input and said fourth input for programmably selecting said first delayed signal.
Claim 7
Dependent Claim
25 words
An apparatus as set forth in claim 5 wherein said second output is coupled to said first multiplexer for programmably selecting said second delayed signal.
Claim 8
Dependent Claim
21 words
An apparatus as set forth in claim 1 wherein said third period is equal to a fraction of said first period.
Claim 9
Dependent Claim
16 words
An apparatus as set forth in claim 7 wherein said fraction is equal to one half.
Claim 10
Dependent Claim
25 words
An apparatus as set forth in claim 1 wherein said third period being equal to said first period plus a fraction of said second period.
Claim 11
Dependent Claim
16 words
An apparatus as set forth in claim 9 wherein said fraction is equal to one half.
Claim 12
Dependent Claim
18 words
An apparatus as set forth in claim 1 wherein said first and said second delay elements are inverters.
Claim 13
Dependent Claim
104 words
An apparatus as set forth in claim 1 wherein said first delay element has a fifth input for receiving a second input signal and a third output for producing a third delay signal, said third delay signal being a second representation of said second input signal delayed by said first period; and said second delay element has a sixth input for receiving said third delayed signal and a fourth output for producing a fourth delayed signal, said third output is coupled to said sixth input and said fourth delayed signal is a non-inverted version of said third delayed signal delayed by said second period.
Claim 14
Dependent Claim
22 words
An apparatus as set forth in claim 12 wherein said second input signal is an inverted version of said first input signal.
Claim 15
Dependent Claim
22 words
An apparatus as set forth in claim 12 wherein said third delayed signal is an inverted version of said first delayed signal.
Claim 16
Dependent Claim
22 words
An apparatus as set forth in claim 12 wherein said fourth delayed signal is an inverted version of said second delayed signal.
Claim 17
Dependent Claim
45 words
Apparatus of claim 12 further comprising: a first multiplexer coupled between said first input and said third input for programmably selecting said first input signal; and a second multiplexer coupled between said sixth input and said fourth input for programmably selecting said third delayed signal.
Claim 18
Dependent Claim
25 words
An apparatus as set forth in claim 16 wherein said second output is coupled to said first multiplexer for programmably selecting said second delayed signal.
Claim 19
Dependent Claim
21 words
An apparatus as set forth in claim 16 wherein said third period is equal to a fraction of said first period.
Claim 20
Dependent Claim
16 words
An apparatus as set forth in claim 18 wherein said fraction is equal to one half.
Claim 21
Dependent Claim
25 words
An apparatus as set forth in claim 17 wherein said third period is equal to said first period plus a fraction of said second period.
Claim 22
Dependent Claim
16 words
An apparatus as set forth in claim 20 wherein said fraction is equal to one half.
Claim 23
Dependent Claim
59 words
Apparatus of claim 12 further comprising: a first multiplexer coupled between said first and second inputs and said third input for programmably selecting said first input signal and said first delayed signal; and a second multiplexer coupled between said fifth and sixth inputs and said fourth input for programmably selecting said second input signal and said third delayed signal.
Claim 24
Dependent Claim
37 words
An apparatus as set forth in claim 22 wherein said second output is coupled to said first multiplexer and said fourth output is coupled to said second multiplexer for programmably selecting said second and fourth delayed signal.
Claim 25
Dependent Claim
31 words
An apparatus as set forth in claim 23 wherein if said first and said sixth inputs are programmably selected, said third period is equal to a fraction of said first period.
Claim 26
Dependent Claim
16 words
An apparatus as set forth in claim 24 wherein said fraction is equal to one half.
Claim 27
Dependent Claim
31 words
An apparatus as set forth in claim 23 wherein if said fifth and said second inputs are programmably selected, said third period is equal to a fraction of said first period.
Claim 28
Dependent Claim
16 words
An apparatus as set forth in claim 26 wherein said fraction is equal to one half.
Claim 29
Dependent Claim
27 words
An apparatus as set forth in claim 23 wherein if said second and sixth inputs are programmably selected, said third period is equal to said first period.
Claim 30
Dependent Claim
36 words
An apparatus as set forth in claim 23 wherein if said second input and said fourth output are programmably selected, said third period is equal to said first period plus a fraction of said second period.
Claim 31
Dependent Claim
16 words
An apparatus as set forth in claim 29 wherein said fraction is equal to one half.
Claim 32
Dependent Claim
36 words
An apparatus as set forth in claim 23 wherein if said sixth input and said second output are programmably selected, said third period is equal to said first period plus a fraction of said second period.
Claim 33
Dependent Claim
16 words
An apparatus as set forth in claim 31 wherein said fraction is equal to one half.
Claim 34
Dependent Claim
32 words
An apparatus as set forth in claim 23 wherein if said second and said fourth outputs are programmably selected, said third period is equal to said first period plus said second period.
Claim 35
Dependent Claim
19 words
An apparatus as set forth in claim 1 wherein said first and said second delay elements are differential delays.
Claim 36
Independent Claim
109 words
A method of delaying an input signal comprising the steps of: delaying said input signal to produce a first delayed signal, said first delayed signal being a representation of said input signal delayed by a first period; delaying said first delayed signal to produce a second delayed signal, said second delayed signal being said representation of said first delayed signal delayed by a second period; comparing said input signal and said first delayed signal to produce a first output signal, said first output signal being said input signal delayed by a third period plus any delay caused by said comparing of said input signal and said first delayed signal.
Claim 37
Independent Claim
109 words
A method of delaying an input signal comprising the steps of: delaying said input signal to produce a first delayed signal, said first delayed signal being a representation of said input signal delayed by a first period; delaying said first delayed signal to produce a second delayed signal, said second delayed signal being said representation of said first delayed signal delayed by a second period; comparing said input signal and said first delayed signal to produce a first output signal, said first output signal being said input signal delayed by a third period plus any delay caused by said comparing of said input signal and said first delayed signal.
Claim 38
Dependent Claim
53 words
The method of claim 35 further comprising the step of: comparing said first delayed signal and said second delayed signal to produce a second output signal, said second output signal being delayed by a fourth period plus any delay caused by said comparing of said first delayed signal and said second delayed signal.
Claim 39
Dependent Claim
43 words
The method of claim 35 further comprising the steps of: inputting said input signal to a first multiplexing element for programmably selecting said input signal; and inputting said first delayed signal to a second multiplexing element for programmably selecting said first delayed signal.
Claim 40
Dependent Claim
27 words
The method of claim 37 further comprising the step of: inputting said second delayed signal to said first multiplexing element for programmably selecting said second delayed signal.
Claim 41
Dependent Claim
11 words
The method of claim 35 wherein said representation is an inversion.
Claim 42
Dependent Claim
18 words
The method of claim 35 wherein said third period is equal to a fraction of said first period.
Claim 43
Dependent Claim
13 words
The method of claim 40 wherein said fraction is equal to one half.
Claim 44
Dependent Claim
22 words
The method of claim 36 wherein said fourth period is equal to said first period plus a fraction of said second period.
Claim 45
Dependent Claim
13 words
The method of claim 42 wherein said fraction is equal to one half.
Claim 46
Independent Claim
163 words
A method of delaying an input signal comprising the steps of: inputting a first input signal to a first input of a first delay element; inputting a second input signal to a second input of said first delay element; delaying said first input signal in said first delay element to produce a first delayed signal, said first delayed signal being said first input signal delayed by a first period; delaying said second input signal in said first delay element to produce a second delayed signal, said second delayed signal being said second input signal delayed by said first period; comparing one of said first and second input signals with one of said first and second delayed signals to produce a first output signal, said first output signal being said first input signal delayed by a second period plus any delay caused by said comparing of said one of said first and second input signals with one of said first and second delayed signals.
Claim 47
Independent Claim
163 words
A method of delaying an input signal comprising the steps of: inputting a first input signal to a first input of a first delay element; inputting a second input signal to a second input of said first delay element; delaying said first input signal in said first delay element to produce a first delayed signal, said first delayed signal being said first input signal delayed by a first period; delaying said second input signal in said first delay element to produce a second delayed signal, said second delayed signal being said second input signal delayed by said first period; comparing one of said first and second input signals with one of said first and second delayed signals to produce a first output signal, said first output signal being said first input signal delayed by a second period plus any delay caused by said comparing of said one of said first and second input signals with one of said first and second delayed signals.
Claim 48
Dependent Claim
23 words
The method of claim 44 wherein said first input signal is compared with said second delayed signal to produce said first output signal.
Claim 49
Dependent Claim
23 words
The method of claim 44 wherein said first delayed signal is compared with said second input signal to produce said first output signal.
Claim 50
Dependent Claim
31 words
The method of claim 44 wherein said second input is an inverted version of said first input, and said second delayed signal is an inverted version of said first delayed signal.
Claim 51
Dependent Claim
16 words
The method of claim 44 wherein said second period is a fraction of said first period.
Claim 52
Dependent Claim
13 words
The method of claim 48 wherein said fraction is equal to one half.
Claim 53
Dependent Claim
56 words
The method of claim 44 further comprising the step of: comparing said first delayed signal and said second delayed signal to produce a third output signal, said third output signal being said first input signal delayed by said first period plus any delay caused by said comparing of said delayed signal and said second delayed signal.
Claim 54
Dependent Claim
163 words
The method of claim 44 further comprising the steps of: inputting said first delayed signal to a first input of a second delay element; inputting said second delayed signal to a second input of said second delay element; delaying said first delayed signal in said second delay element to produce a third delayed signal, said third delayed signal being said first delayed signal delayed by a third period; delaying said second delayed signal in said second delay element to produce a fourth delayed signal, said fourth delayed signal being said second delayed signal delayed by said third period; and comparing one of said first and second delayed signals with one of said third and fourth delayed signal to produce a fourth output signal, said fourth output signal being said first input signal delayed by a fourth period plus any delay caused by said comparing of said one of said first and second delayed signals with one of said third and fourth delayed signals.
Claim 55
Dependent Claim
23 words
The method of claim 51 wherein said first delayed signal is compared with said fourth delayed signal to produce said fourth output signal.
Claim 56
Dependent Claim
23 words
The method of claim 51 wherein said third delayed signal is compared with said second delayed signal to produce said fourth output signal.
Claim 57
Dependent Claim
22 words
The method of claim 51 wherein said fourth period is equal to said first period plus a fraction of said third period.
Claim 58
Dependent Claim
12 words
The method claim 54 wherein said fraction is equal to one half.
Claim 59
Dependent Claim
61 words
The method of claim 51 further comprising the step of: comparing said third delayed signal and said fourth delayed signal to produce a fifth output signal, said fifth output signal being said first input signal delayed by said first period plus said third period plus any delay caused by said comparing of said third delayed signal and said fourth delayed signal.
Claim 60
Dependent Claim
92 words
The method claim 51 further comprising the steps of: inputting said first input signal, said first delayed signal, and said third delayed signal to a first multiplexer for programmably selecting among said first input signal, said first delayed signal, and said third delayed signal; and inputting said second input signal, said second delayed signal, and said fourth delayed signal to a second multiplexer for programmably selecting among said second input signal, said second delayed signal, and said fourth delayed signal, said first multiplexer and said second multiplexer being coupled to a comparator.
Claim 61
Dependent Claim
14 words
The method of claim 44 wherein said first delay element is a differential delay.
Claim 62
Dependent Claim
14 words
The method of claim 51 wherein said second delay element is a differential delay.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-12-19 | 1998-06-20 | 1998-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-12-19 | 2002-06-20 | 2002-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-12-19 | 2006-06-20 | 2006-12-20 | $7700.00 | Window Closed / Lapsed |