US4243940A
Expired / Lapsed
US
⏱️ 0.0 years remaining
AC to DC converter for antiskid systems
Assignee: Lockheed Martin Tactical Systems Inc
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Filing: 1978-12-07
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Granted: 1981-01-06
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Expires: 1998-12-07
Abstract
Abstract A circuit for converting AC signals from a wheel speed transducer to a varying DC level indicative of the instantaneous rotational speed of the wheel of a vehicle. The invention includes a squaring circuit receiving a sinusoidal input from a wheel speed transducer and producing a fixed amplitude square wave of a frequency equivalent to that of the sinusoidal input. A pulsing circuit receives the square wave signal and produces a series of fixed duration pulses of a frequency double that of the sinusoidal signal. These pulses are applied to an integrator which produces a DC output of an amplitude characteristic of the frequency of the sinusoidal input. The integrator has a characteristic phase lag associated therewith resulting in a tendency of the phase of the superimposed AC output, caused by cyclic changes in the frequency of the transducer output, to lag the phase of the associated wheel speed change. A lead network is designed into the integrator to compensate for such phase lag and to cause the instantaneous amplitude of the DC output to more closely correlate with the associated change in wheel speed.
Inventors
- 👤 Edgar J. Ruof
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:45
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/17; B60T8/172; B60L; B60L3/00; B60L3/10
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
141 words
In an antiskid system having a wheel speed transducer producing a sinusoidal signal, the improvement of an AC to DC converter, comprising: a squaring circuit receiving the sinusoidal signal and producing a corresponding square wave output; a pulsing circuit connected to said squaring circuit and producing pulses of a frequency determined by the frequency of said square wave output; an integrator having first and second inputs, each connected to said pulsing circuit through a uniquely associated resistor and capacitor, said integrator converting said pulses to a DC output having an amplitude corresponding to the frequency of said pulses, said integrator tending to create a phase lag between variations in amplitude of said DC output signal and changes in frequency of the sinusoidal signal; and a capacitor connected in a positive feedback loop across said integrator for compensating for said phase lag.
Claim 2
Dependent Claim
141 words
In an antiskid system having a wheel speed transducer producing a sinusoidal signal, the improvement of an AC to DC converter, comprising: a squaring circuit receiving the sinusoidal signal and producing a corresponding square wave output; a pulsing circuit connected to said squaring circuit and producing pulses of a frequency determined by the frequency of said square wave output; an integrator having first and second inputs, each connected to said pulsing circuit through a uniquely associated resistor and capacitor, said integrator converting said pulses to a DC output having an amplitude corresponding to the frequency of said pulses, said integrator tending to create a phase lag between variations in amplitude of said DC output signal and changes in frequency of the sinusoidal signal; and a capacitor connected in a positive feedback loop across said integrator for compensating for said phase lag.
Claim 3
Dependent Claim
32 words
The improvement in an AC to DC converter according to claim 1 wherein said pulsing circuit is a frequency doubler, said pulses being of a frequency twice that of the sinusoidal input.
Claim 4
Dependent Claim
40 words
The improvement in an AC to DC converter according to claim 1 wherein said resistor and capacitor connected to said first input comprise a charging circuit and said resistor and capacitor connected to said second input comprise a discharging circuit.
Claim 5
Dependent Claim
28 words
The improvement in an AC to DC converter according to claim 1 wherein said first input and second input are respectively positive and negative inputs to said integrator.
Claim 6
Dependent Claim
33 words
The improvement in an AC to DC converter according to claim 1 wherein said integrator includes filter means connected to said first and second inputs thereof for filtering ripple from said DC output.
Claim 7
Dependent Claim
30 words
The improvement in an AC to DC converter according to claim 1 wherein said squaring circuit includes an amplifier having a hysteresis feedback loop connected to the positive input thereof.
Claim 8
Dependent Claim
54 words
The improvement in an AC to DC converter according to claim 6 wherein said amplifier has a negative input biased by a voltage divider, said hysteresis feedback loop being connected to said voltage divider, and wherein a filter capacitor is connected to said voltage divider to decouple said negative input from said hysteresis loop.
Claim 9
Dependent Claim
146 words
An AC to DC converter for an antiskid system, comprising: first circuit means for receiving a sinusoidal signal and converting said sinusoidal signal into a pulsating signal; an integrator having positive and negative inputs connected to said first circuit means, receiving said pulsating signal and producing a DC signal of an amplitude corresponding to the frequency of said pulsating signal, said integrator tending to introduce a phase lag between amplitude changes in said DC signal and frequency changes in said sinusoidal signal; a positive feedback circuit comprising a capacitor connected across said integrator, functioning as a lead network, bringing the phase of said DC signal and said sinusoidal signal into substantial synchronization; and a charging resistive and capacitive circuit interconnected between said positive input and said first circuit means and a discharging resistive and capacitive circuit interconnected between said negative input and said first circuit means.
Claim 10
Dependent Claim
146 words
An AC to DC converter for an antiskid system, comprising: first circuit means for receiving a sinusoidal signal and converting said sinusoidal signal into a pulsating signal; an integrator having positive and negative inputs connected to said first circuit means, receiving said pulsating signal and producing a DC signal of an amplitude corresponding to the frequency of said pulsating signal, said integrator tending to introduce a phase lag between amplitude changes in said DC signal and frequency changes in said sinusoidal signal; a positive feedback circuit comprising a capacitor connected across said integrator, functioning as a lead network, bringing the phase of said DC signal and said sinusoidal signal into substantial synchronization; and a charging resistive and capacitive circuit interconnected between said positive input and said first circuit means and a discharging resistive and capacitive circuit interconnected between said negative input and said first circuit means.
Claim 11
Dependent Claim
16 words
The AC to DC converter as recited in claim 8 wherein said integrator comprises an amplifier.
Claim 12
Dependent Claim
29 words
The AC to DC converter as recited in claim 9 wherein said amplifier further includes filter means connected to each input thereof for reducing ripple in said DC signal.
Claim 13
Dependent Claim
30 words
The AC to DC converter as recited in claim 9 wherein said integrator further includes a second capacitor interconnected between the output of said amplifier and the negative input thereof.
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) | 1984-01-06 | 1984-07-07 | 1985-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-06 | 1988-07-07 | 1989-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-06 | 1992-07-07 | 1993-01-06 | $7700.00 | Window Closed / Lapsed |