Patent US3950989A successfully refreshed from Google Patents.
US3950989A
Expired / Lapsed
US
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DC to frequency conversion circuit
Assignee: Individual
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Filing: 1974-07-30
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Granted: 1976-04-20
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Expires: 1994-07-30
Abstract
Abstract A circuit for converting an input DC value to a pulse signal of a given frequency, and including an integration circuit which receives as its input a composite DC signal which includes the DC value, and provides an integrated output therefrom. A hysteresis amplifier receives the integrated output, and in response thereto provides a binary output signal. A switching device having two states receives the binary output signal, and in response thereto, respectively switches between its two states. A pulse generating circuit is coupled to the switching device and produces a sequence of fixed pulses at a predetermined, noncritical rate. The switching device only permits the fixed pulses to be transmitted during one of its states. An output circuit which includes a counting device is coupled to the switching means and receives the fixed pulses which are transmitted by the switching device and counts them. A frequency to DC conversion circuit is coupled in a feed back arrangement between the switching device and the integration circuit for converting into a DC level the average pulse rate which the switching devices transmits. The DC level in conjunction with the input DC value forms the composite DC signal. The total number of pulses counted per unit time will depend upon the composite DC signal. In a specific embodiment, the DC to frequency conversion circuit is incorporated in a fuel flow system for providing a pulse count output representing the amount of fuel consumed. The aforementioned Abstract is neither intended to define the invention of the application which, of course, is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
Inventors
- 👤 Richard L. Meirowitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:54
CPC Classifications
G; G01; G01F; G01F15/00; G01F15/07; G01F15/075; G01F15/0755
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
174 words
A circuit for converting a DC value to a pulse signal comprising, integration circuit means receiving a composite DC input signal and providing an integrated output, hysteresis amplifier means receiving said integrated output and in response thereto providing a binary level output signal, switch means having two states and receiving said binary level output signal and in response thereto respectively switching between its two states, pulse generating means coupled to said switch means for providing a sequence of fixed pulses at a predetermined rate, said switch means transmitting said pulses only during one of its states, output circuit means including counting means coupled to said switch means for receiving said transmitted fixed pulses and counting them, and frequency to DC conversion means coupled between said switch means and said integration circuit means for receiving said transmitted pulses and converting them into a DC level, said DC level in combination with said DC value forming said composite DC input signal, whereby the total number of pulses counted is dependent upon said composite DC input signal.
Claim 2
Dependent Claim
174 words
A circuit for converting a DC value to a pulse signal comprising, integration circuit means receiving a composite DC input signal and providing an integrated output, hysteresis amplifier means receiving said integrated output and in response thereto providing a binary level output signal, switch means having two states and receiving said binary level output signal and in response thereto respectively switching between its two states, pulse generating means coupled to said switch means for providing a sequence of fixed pulses at a predetermined rate, said switch means transmitting said pulses only during one of its states, output circuit means including counting means coupled to said switch means for receiving said transmitted fixed pulses and counting them, and frequency to DC conversion means coupled between said switch means and said integration circuit means for receiving said transmitted pulses and converting them into a DC level, said DC level in combination with said DC value forming said composite DC input signal, whereby the total number of pulses counted is dependent upon said composite DC input signal.
Claim 3
Dependent Claim
48 words
The circuit as in claim 1 and wherein said integration circuit means is a feedback amplifier including a capacitor means in its feedback loop and wherein the output of said feedback amplifier is a ramp signal, the slope of which is controlled by said composite DC input signal.
Claim 4
Dependent Claim
76 words
The circuit as in claim 2 and wherein said hysteresis amplifier has a lower trip point which is less than zero volts, and an upper trip point greater than zero volts, such that when said ramp signal decreases to said lower trip point a negative level output signal is produced from said hysteresis amplifier and when said ramp signal increases to said upper trip point a positive level output signal is produced from said hysteresis amplifier.
Claim 5
Dependent Claim
41 words
The circuit as in claim 3 and wherein said DC value is a positive voltage and said DC level is a negative voltage and wherein the magnitude of said DC level is substantially greater than the magnitude of said DC value.
Claim 6
Dependent Claim
82 words
The circuit as in claim 4 and wherein the time duration of said one state of said switch means is substantially fixed and the time duration of the other state is essentially determined by said DC value, whereby the same number of fixed pulses are transmitted during each of said one state of said switch means, said fixed number of pulses establishing a pulse group, and whereby the frequency of occurrence of said pulse group is essentially determined by said DC value.
Claim 7
Dependent Claim
32 words
The circuit of claim 1 and wherein said output circuit further comprises frequency divider means for dividing down the number of transmitted pulses so that only a proportional amount will be counted.
Claim 8
Dependent Claim
24 words
The circuit of claim 1 and further comprising attenuation means for attenuating said DC value prior to its being combined with said DC level.
Claim 9
Dependent Claim
142 words
The circuit of claim 1 and wherein said frequency to DC conversion means further comprises amplifier means receiving said transmitted pulses, first switching means coupled to a fixed voltage supply and controlled by the output of said amplifier means for respectively switching between two states in response to said transmitted pulses, second switching means having the same two states and controlled by the output of said amplifier means to operate in opposition to said first switching means, capacitor means coupled between said first and second switching means, and resistor means coupled between said second switching means and said integration circuit means, whereby during one combination of states of said first and second switching means said capacitor means is charged to the voltage of said fixed voltage supply, and during the other combination of states said capacitor means discharges through said resistor means.
Claim 10
Dependent Claim
88 words
The circuit as in claim 8 and wherein said fixed voltage supply is zener controlled voltage and wherein said frequency to DC conversion circuit further comprises fixed resistor means serially connected between said voltage supply and said first switching means and variable resistor means coupled across said first switching means, wherein said fixed resistor means and said variable resistor means form a voltage divider whose output voltage is controlled by said variable resistor means, and wherein said capacitor means charges to the output voltage of said voltage divider.
Claim 11
Dependent Claim
22 words
The circuit as in claim 1 and wherein said output circuit means further comprises buffer circuit means for isolating said counting means.
Claim 12
Dependent Claim
246 words
A fuel flow measuring system comprising, in combination, turbine flow transmitter means adapted to be inserted in a fuel line and producing an output frequency representing the amount of fuel passing therethrough, control circuit means receiving said output frequency and converting it into a DC value representing the flow rate of the fuel, and totalizing signal circuit means receiving said DC value and producing a pulse signal representing the total fuel consumed, and wherein said totalizing signal circuit means further comprises: integration circuit means receiving a composite DC input signal and providing an integrated output, hysteresis amplifier means receiving said integrated output and in response thereto providing a binary level output signal; switch means having two states and receiving said binary level output signal and in response thereto respectively switching between its two states; pulse generating means coupled to said switch means for providing a sequence of fixed pulses at a pre-determined, not necessarily periodic rate, said switch means transmitting said pulses only during one of its states; output circuit means including counting means coupled to said switch means for receiving said transmitted fixed pulses and counting them; and frequency to DC conversion means coupled between said switch means and said integration circuit means for receiving said transmitted pulses and converting them into a DC level, said DC level in combination with said DC value forming said composite DC input signal, whereby the total number of pulses counted is dependent upon said composite DC input signal.
Claim 13
Dependent Claim
246 words
A fuel flow measuring system comprising, in combination, turbine flow transmitter means adapted to be inserted in a fuel line and producing an output frequency representing the amount of fuel passing therethrough, control circuit means receiving said output frequency and converting it into a DC value representing the flow rate of the fuel, and totalizing signal circuit means receiving said DC value and producing a pulse signal representing the total fuel consumed, and wherein said totalizing signal circuit means further comprises: integration circuit means receiving a composite DC input signal and providing an integrated output, hysteresis amplifier means receiving said integrated output and in response thereto providing a binary level output signal; switch means having two states and receiving said binary level output signal and in response thereto respectively switching between its two states; pulse generating means coupled to said switch means for providing a sequence of fixed pulses at a pre-determined, not necessarily periodic rate, said switch means transmitting said pulses only during one of its states; output circuit means including counting means coupled to said switch means for receiving said transmitted fixed pulses and counting them; and frequency to DC conversion means coupled between said switch means and said integration circuit means for receiving said transmitted pulses and converting them into a DC level, said DC level in combination with said DC value forming said composite DC input signal, whereby the total number of pulses counted is dependent upon said composite DC input signal.
Claim 14
Dependent Claim
29 words
The circuit as in claim 11 and wherein said counting means is a mechanical counter including reset means for setting the count of the counter to a predetermined value.
Claim 15
Dependent Claim
28 words
The circuit as in claim 12 and wherein said totalizing circuit means further comprises summing amplifier means for combining the outputs of at least two control circuit means.
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) | 1979-04-20 | 1979-10-20 | 1980-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-20 | 1983-10-20 | 1984-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-20 | 1987-10-20 | 1988-04-20 | $7700.00 | Window Closed / Lapsed |