Patent US3879676A successfully refreshed from Google Patents.
US3879676A
Expired / Lapsed
US
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Pulse train filter circuit particularly for automotive tachogenerators
Assignee: Robert Bosch GmbH
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Filing: 1973-07-18
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Granted: 1975-04-22
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Expires: 1993-07-18
Abstract
Abstract A voltage controlled oscillator is kept in step with an incoming train of pulses by a phase-locked loop containing a pulse comparator operating as an EXCLUSIVE OR gate followed by a regulating amplifier that partially integrates while also transmitting the signal to the frequency control of the oscillator. Effective phase-locked operation of the oscillator over a wider frequency range or for more rapid frequency changes is provided by an auxiliary control circuit fed by the same input pulses, which integrates the input with a slight delay and acts as a low-pass circuit passing frequencies within the full range of the input pulse repetition frequencies. The phase-locked loop control and the auxiliary control are combined for control of the oscillator frequency either in a simple summing circuit or through a limiter, which gives control to the auxiliary circuit when the frequency changes sharply. The circuit is particularly useful for filtering out irregularities from the signal of a tachogenerator that corresponds to the velocity of a wheel of a motor vehicle, and in this application the circuit can be arranged to yield an acceleration signal as well as a filtered velocity signal.
Inventors
- 👤 Alfred Schulz
- 👤 Gunther Honig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:18
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/17; B60T8/172; H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/085
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
209 words
A pulse train filter circuit for a pulse train of varying frequency comprising: a phase comparison circuit (10) having a first input for receiving an input pulse train and a second input (102) for receiving an output pulse train; a pulse train generating oscillator (12) of voltage controlled frequency for supplying an output pulse train to an output circuit and to said second input (102) of said comparison circuit (10); a regulating circuit (11) having its input connected to the output of said comparison circuit (10) and its output connected for frequency control of said oscillator (12), for converting the output of said comparison circuit (10) to a control voltage of suitable characteristics and magnitude range for causing the output pulses of said oscillator (12) to keep in step with pulses of said input pulse train, and an auxiliary control circuit for increasing the capture range of the frequency control of said oscillator, containing a low-pass circuit (18) to which is supplied the same input frequency (f1) as said comparison circuit (10), said auxiliary control circuit (18) continuously furnishing a control voltage of constant polarity to which the frequency control of said output (12) is responsive in addition to being responsive to the output of said regulating circuit (11).
Claim 2
Dependent Claim
209 words
A pulse train filter circuit for a pulse train of varying frequency comprising: a phase comparison circuit (10) having a first input for receiving an input pulse train and a second input (102) for receiving an output pulse train; a pulse train generating oscillator (12) of voltage controlled frequency for supplying an output pulse train to an output circuit and to said second input (102) of said comparison circuit (10); a regulating circuit (11) having its input connected to the output of said comparison circuit (10) and its output connected for frequency control of said oscillator (12), for converting the output of said comparison circuit (10) to a control voltage of suitable characteristics and magnitude range for causing the output pulses of said oscillator (12) to keep in step with pulses of said input pulse train, and an auxiliary control circuit for increasing the capture range of the frequency control of said oscillator, containing a low-pass circuit (18) to which is supplied the same input frequency (f1) as said comparison circuit (10), said auxiliary control circuit (18) continuously furnishing a control voltage of constant polarity to which the frequency control of said output (12) is responsive in addition to being responsive to the output of said regulating circuit (11).
Claim 3
Dependent Claim
209 words
A pulse train filter circuit for a pulse train of varying frequency comprising: a phase comparison circuit (10) having a first input for receiving an input pulse train and a second input (102) for receiving an output pulse train; a pulse train generating oscillator (12) of voltage controlled frequency for supplying an output pulse train to an output circuit and to said second input (102) of said comparison circuit (10); a regulating circuit (11) having its input connected to the output of said comparison circuit (10) and its output connected for frequency control of said oscillator (12), for converting the output of said comparison circuit (10) to a control voltage of suitable characteristics and magnitude range for causing the output pulses of said oscillator (12) to keep in step with pulses of said input pulse train, and an auxiliary control circuit for increasing the capture range of the frequency control of said oscillator, containing a low-pass circuit (18) to which is supplied the same input frequency (f1) as said comparison circuit (10), said auxiliary control circuit (18) continuously furnishing a control voltage of constant polarity to which the frequency control of said output (12) is responsive in addition to being responsive to the output of said regulating circuit (11).
Claim 4
Dependent Claim
209 words
A pulse train filter circuit for a pulse train of varying frequency comprising: a phase comparison circuit (10) having a first input for receiving an input pulse train and a second input (102) for receiving an output pulse train; a pulse train generating oscillator (12) of voltage controlled frequency for supplying an output pulse train to an output circuit and to said second input (102) of said comparison circuit (10); a regulating circuit (11) having its input connected to the output of said comparison circuit (10) and its output connected for frequency control of said oscillator (12), for converting the output of said comparison circuit (10) to a control voltage of suitable characteristics and magnitude range for causing the output pulses of said oscillator (12) to keep in step with pulses of said input pulse train, and an auxiliary control circuit for increasing the capture range of the frequency control of said oscillator, containing a low-pass circuit (18) to which is supplied the same input frequency (f1) as said comparison circuit (10), said auxiliary control circuit (18) continuously furnishing a control voltage of constant polarity to which the frequency control of said output (12) is responsive in addition to being responsive to the output of said regulating circuit (11).
Claim 5
Dependent Claim
25 words
A pulse train filter circuit as defined in claim 1, in which said phase comparison circuit (10) has the characteristics of an EXCLUSIVE OR gate.
Claim 6
Dependent Claim
36 words
A pulse train filter circuit as defined in claim 1, in which a frequency division circuit (16) is interposed between the output of said oscillator (12) and said second input (102) of said comparison circuit (10).
Claim 7
Dependent Claim
47 words
A pulse train filter circuit as defined in claim 1, in which the frequency control of said oscillator is connected to the output of a summing circuit (17), the two inputs of which are connected respectively to said low-pass circuit (18) and to said regulating circuit (11).
Claim 8
Dependent Claim
50 words
A pulse train circuit as defined in claim 4, in which an amplitude control means (117) is interposed between at least one of the inputs of said summing circuit (17) and the preceding circuit (11 or 18) that supplies a voltage signal to such input of said summing circuit (17).
Claim 9
Dependent Claim
66 words
A pulse train filter circuit as defined in claim 1, in which a limiting circuit (30) is interposed between the output of said low-pass circuit (18) and the frequency control of said oscillator (12) for limiting the extend to which the frequency control voltage of said oscillator may be caused by said regulating circuit (11) to deviate from the output voltage of said low-pass circuit (18).
Claim 10
Dependent Claim
26 words
A pulse train filter circuit as defined in claim 6, in which said limiting circuit (30) contains at least two diodes (301, 303) in antiparallel connection.
Claim 11
Dependent Claim
37 words
A pulse train filter circuit as defined in claim 7, in which said limiting circuit (30) comprises two series chains each of a plurality of diodes (301, 302, 303, 304), said chains being combined in antiparallel connection.
Claim 12
Dependent Claim
98 words
A pulse train filter circuit as defined in claim 1, in which a limiting circuit is interposed between the output of said low-pass circuit (18) and the frequency control of said oscillator (12) for limiting the extent to which the frequency control voltage of said oscillator may be caused by said regulating circuit (11) to deviate from the output voltage of said low-pass circuit (18), said limiting circuit comprising two parallel-connected semiconductor switching devices (310, 311), the respective control electrodes of said semiconductor switching devices (310, 311) being each connected with a voltage sensitive threshold switch (311, 232).
Claim 13
Dependent Claim
22 words
A pulse train filter circuit as defined in claim 9, in which said semiconductor switching devices (310, 311) are field effect transistors.
Claim 14
Dependent Claim
56 words
A pulse train filter circuit as defined in claim 9, in which both of said voltage sensitive threshold switches (313, 323) comprise operational amplifiers having differential inputs, each of said operational amplifiers having one input connected with the output of said regulating circuit (11) and another input connected with the output of said low-pass circuit (18).
Claim 15
Dependent Claim
45 words
A pulse train filter circuit as defined in claim 11, in which an amplitude adjusting means (316) is interposed between at least one of the inputs of said operational amplifiers (313, 323) and the output of the stage (18, 11) supplying an electrical signal thereto.
Claim 16
Dependent Claim
54 words
A pulse train filter circuit as defined in claim 1, in which said regulating circuit (11) comprises an operational amplifier (110) arranged to provide regulation in a combined proportional-integral mode by virtue of a resistor (111) and a capacitor (112) connected in series to provide a negative feedback path for said operational amplifier (110).
Claim 17
Dependent Claim
57 words
A pulse train filter circuit as defined in claim 13, in which means are provided for applying a constant correction voltage to said operational amplifier (110) of said regulating circuit (11) for setting a constant phase difference in the phase regulation applied to said oscillator (12) by said phase comparison circuit (10) and said regulating circuit (11).
Claim 18
Dependent Claim
29 words
A pulse train filter circuit as defined in claim 1, in which said regulating circuit (11) is provided in a form having a combined proportional and integral regulating characteristic.
Claim 19
Dependent Claim
31 words
A pulse train filter circuit as defined in claim 1, in which said regulating circuit (11) is constituted by a proportional regulator (33) and an integrating regulator (34) operating in series.
Claim 20
Dependent Claim
56 words
A pulse train filter circuit as defined in claim 16, in which means are provided including a smoothing circuit (28) with its input connected to the output of said proportional regulating circuit (33) for generating a direct current voltage signal that is proportional to the first derivative with respect to time of the input frequency (f1).
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) | 1978-04-21 | 1978-10-21 | 1979-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-21 | 1982-10-21 | 1983-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-21 | 1986-10-21 | 1987-04-22 | $7700.00 | Window Closed / Lapsed |