US3916296A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Distortion analyzer with automatic tuning circuit
Assignee: Hewlett Packard Japan Inc
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Filing: 1974-12-16
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Granted: 1975-10-28
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Expires: 1994-12-16
Abstract
Abstract An apparatus utilizing a parallel-T circuit bridge achieves improved low distortion measurements. To tune the bridge, two of the bridge components that do not interact with each other in the vicinity of the frequency to which the circuit is being tuned, are made variable. By adjusting these components, the bridge is easily adjustable without a large number of adjustments and readjustments. Since there is little interaction between these components, this circuit configuration is easily adaptable to automatic tuning.
Inventors
- 👤 Yoh Narimatsu
- 👤 Shiro Kito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:10
CPC Classifications
G; G01; G01R; G01R23/00; G01R23/16; G01R23/20; H; H03; H03J; H03J3/00; H03J3/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
202 words
An automatic distortion analyzer circuit comprising: a parallel-T circuit including: a first T circuit including two fixed resistors and a variable capacitor; a second T circuit including two fixed capacitors and a variable resistor; said variable capacitor being variable in response to a first error signal applied thereto; and said variable resistor being variable in response to a second error signal applied thereto; a first phase shifter connected to the input of said parallel-T circuit bridge for producing a negative phase shift of the input signal; a second phase shifter connected to the input of said parallel-T circuit briDge for producing a positive phase shift of the input signal; a first synchronous phase detector connected to receive the output signal of said first phase shifter and the output signal of said parallel-T circuit for producing a first error signal; a second synchronous phase detector connected to receive the output signal of said second phase shifter and the output signal of said parallel-T circuit for producing a second error signal; means for varying the impedance of said variable capacitor in response to said first error signal; and means for varying the impedance of said variable resistor in response to said second error signal.
Claim 2
Dependent Claim
202 words
An automatic distortion analyzer circuit comprising: a parallel-T circuit including: a first T circuit including two fixed resistors and a variable capacitor; a second T circuit including two fixed capacitors and a variable resistor; said variable capacitor being variable in response to a first error signal applied thereto; and said variable resistor being variable in response to a second error signal applied thereto; a first phase shifter connected to the input of said parallel-T circuit bridge for producing a negative phase shift of the input signal; a second phase shifter connected to the input of said parallel-T circuit briDge for producing a positive phase shift of the input signal; a first synchronous phase detector connected to receive the output signal of said first phase shifter and the output signal of said parallel-T circuit for producing a first error signal; a second synchronous phase detector connected to receive the output signal of said second phase shifter and the output signal of said parallel-T circuit for producing a second error signal; means for varying the impedance of said variable capacitor in response to said first error signal; and means for varying the impedance of said variable resistor in response to said second error signal.
Claim 3
Dependent Claim
36 words
The automatic distortion analyzer as in claim 1 wherein said first phase shifter produces a phase shift of the input signal of substantially -45* + or - n.360*, where n is a positive integer or 0.
Claim 4
Dependent Claim
36 words
The automatic distortion analyzer as in claim 1 wherein said second phase shifter produces a phase shift of the input signal of substantially +45* + or - n.360*, where n is a positive integer or 0.
Claim 5
Dependent Claim
16 words
The automatic distortion analyzer as in claim 1 wherein said variable resistor is a photosensitive resistor.
Claim 6
Dependent Claim
17 words
The automatic distortion analyzer as in claim 1 wherein said variable capacitor is a variable capacitance diode.
Claim 7
Dependent Claim
21 words
The automatic distortion analyzer circuit as in claim 1 wherein said variable capacitor is an active capacitance circuit with variable gain.
Claim 8
Dependent Claim
170 words
An automatic distortion analyzer circuit comprising: a parallel-T circuit including: a first T circuit including two fixed resistors and a variable capacitor; a second T circuit including two fixed capacitors and a variable resistor; said variable capacitor being variable in response to a first error signal applied thereto; and said variable resistor being variable in response to a second error signal applied thereto; a first synchronous phase detector responsive to a signal at the common junction between the two fixed capacitors of said second T circuit and the output signal of said parallel-T circuit for producing a first error signal; a second synchronous phase detector responsive to a signal at the common junction between the two fixed resistors of said first T circuit and the output signal of said parallel-T circuit for producing a second error signal; means for varying the impedance of said variable capacitor in response to said first error signal; and means for varying the impedance of said variable resistor in response to said second error signal.
Claim 9
Dependent Claim
170 words
An automatic distortion analyzer circuit comprising: a parallel-T circuit including: a first T circuit including two fixed resistors and a variable capacitor; a second T circuit including two fixed capacitors and a variable resistor; said variable capacitor being variable in response to a first error signal applied thereto; and said variable resistor being variable in response to a second error signal applied thereto; a first synchronous phase detector responsive to a signal at the common junction between the two fixed capacitors of said second T circuit and the output signal of said parallel-T circuit for producing a first error signal; a second synchronous phase detector responsive to a signal at the common junction between the two fixed resistors of said first T circuit and the output signal of said parallel-T circuit for producing a second error signal; means for varying the impedance of said variable capacitor in response to said first error signal; and means for varying the impedance of said variable resistor in response to said second error signal.
Claim 10
Dependent Claim
17 words
The automatic distortion analyzer circuit as in claim 7 wherein said variable resistor is a photosensitive resistor.
Claim 11
Dependent Claim
18 words
The automatic distortion analyzer circuit as in claim 7 wherein said variable capacitor is a variable capacitance diode.
Claim 12
Dependent Claim
21 words
The automatic distortion analyzer circuit as in claim 7 wherein said variable capacitor is an active capacitance circuit with variable gain.
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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |