US3932741A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit to reduce harmonic distortion in a triangular wave-form function generator
Assignee: HP Inc
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Filing: 1974-09-30
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Granted: 1976-01-13
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Expires: 1994-09-30
Abstract
Abstract A device is disclosed for generating a triangular wave form for use in an electronic function generator. The device employs a level detector which produces a square wave output to drive a triangular function generator in a loop arrangement. Amplitude symmetry of the triangular wave is maintained by sensing the average value and comparing it with a reference level to generate an error signal which in turn serves as a reference input to the level detector. The output of the level detector is therefore corrected to cancel drifts in the average or base line value of the triangular wave form. Time symmetry, or symmetry of the positive and negative slopes of the triangle is maintained by means of a feedback loop utilizing a stable current source. The time symmetry of the square wave is the same as that of the triangle. The square wave is sensed and serves to switch on and off the stable current source. By integrating the current from the current source a voltage is obtained which is proportional to time asymmetries in the square wave. An error signal derived from the integrated current is used in the triangle generator to control either the positive or negative slope of the wave form. A triangular wave form is therefore generated which has both stable amplitude symmetry and time symmetry.
Inventors
- 👤 Raymond C. Hanson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:22
CPC Classifications
H; H03; H03K; H03K4/00; H03K4/06; H03K4/066
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
176 words
A device for generating triangular wave forms comprising: first means for generating a triangular wave form in response to an input signal; level detecting means interconnected in loop configuration with said first means for providing a first square wave signal to said first means in response to said triangular wave form applied at a first input and a level detector reference signal applied at a second input of said level detecting means; integrator means interconnected with said first means for integrating said triangular wave form to produce an average value thereof indicative of the amplitude symmetry of said triangular wave form and comparing said average value with a reference level to produce an amplitude symmetry error signal; and square wave generating means interconnected between said integrator means and said level detecting means for producing a second square wave signal of the same frequency as said first square wave signal and having an amplitude responsive to said amplitude symmetry error signal from said integrator means, said second square wave signal serving as said level detector reference signal.
Claim 2
Independent Claim
176 words
A device for generating triangular wave forms comprising: first means for generating a triangular wave form in response to an input signal; level detecting means interconnected in loop configuration with said first means for providing a first square wave signal to said first means in response to said triangular wave form applied at a first input and a level detector reference signal applied at a second input of said level detecting means; integrator means interconnected with said first means for integrating said triangular wave form to produce an average value thereof indicative of the amplitude symmetry of said triangular wave form and comparing said average value with a reference level to produce an amplitude symmetry error signal; and square wave generating means interconnected between said integrator means and said level detecting means for producing a second square wave signal of the same frequency as said first square wave signal and having an amplitude responsive to said amplitude symmetry error signal from said integrator means, said second square wave signal serving as said level detector reference signal.
Claim 3
Dependent Claim
81 words
A device as in claim 1 further comprising: current generating means for producing an output current responsive to one of said first and second square wave signals; and additional integrating means for integrating said output current to produce a voltage level indicative of the time symmetry of said one square wave and comparing said voltage level with a reference level to produce a time symmetry error signal being applied to said first means to control a slope of said triangular waveform.
Claim 4
Independent Claim
143 words
A device for generating triangular wave forms comprising: first means for generating a triangular wave form in response to an input signal; level detecting means interconnected in loop configuration with said first means for providing a square wave signal to said first means in response to said triangular wave form applied at a first input and a level detector reference signal applied at a second input of said level detecting means; current generating means for producing an output current responsive to said square wave signal; and integrating means for integrating said output current to produce a voltage level indicative of the time symmetry of said square wave and comparing said voltage level with a reference level to produce a time symmetry error signal, said time symmetry error signal being applied to said first means to control a slope of said triangular wave form.
Claim 5
Independent Claim
143 words
A device for generating triangular wave forms comprising: first means for generating a triangular wave form in response to an input signal; level detecting means interconnected in loop configuration with said first means for providing a square wave signal to said first means in response to said triangular wave form applied at a first input and a level detector reference signal applied at a second input of said level detecting means; current generating means for producing an output current responsive to said square wave signal; and integrating means for integrating said output current to produce a voltage level indicative of the time symmetry of said square wave and comparing said voltage level with a reference level to produce a time symmetry error signal, said time symmetry error signal being applied to said first means to control a slope of said triangular wave form.
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) | 1979-01-12 | 1979-07-14 | 1980-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-12 | 1983-07-14 | 1984-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-12 | 1987-07-14 | 1988-01-13 | $7700.00 | Window Closed / Lapsed |