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US 5,210,444 AGranted
Duty cycle meter
AssigneeThe B. F. Goodrich Company
InventorJeffrey W. Johnson
Life of this patent
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AssigneeThe B. F. Goodrich Company
InventorJeffrey W. Johnson
Estimating the term…
A circuit for determining the duty cycle of a control signal includes an oscillator that operates at a frequency that is a predetermined multiple of ten higher than the frequency of the control signal. The oscillator output is connected to the count input of a digital counter, and the control signal is connected to a count inhibit input of the counter. Thus, the counter only counts the oscillator output pulses during the active interval of each cycle of the control signal. Timer means are provided to generate a store trigger signal at the end of a predetermined number of control signal cycles. The store command causes the counter to store and visually display the total count of oscillator pulses detected during the active interval of each cycle. Thus, the count total corresponds to the duty cycle of the control signal. A reset timer is provided to initialize the counter after a predetermined delay from the time that the count total was stored. A threshold timer is provided so that the operator can adjust the circuit to only detect control signal cycles that have a predetermined minimum duty cycle. A timer is also provided to stabilize the counter display over a predetermined time period.
A circuit for determining duty cycle of a control signal having a frequency, said circuit comprising an oscillator, counter means for counting cycles produced by said oscillator and for producing a counter means output that corresponds to said counted cycles, said counter means having a count inhibit input with the control signal being connected to said count inhibit input so that said counter means counts said oscillator cycles during predetermined intervals of the control signal, and delay means for resetting said counter means after the control signal intervals, said oscillator frequency being a predetermined multiple higher than the control signal frequency so that the duty cycle is a function of said counter means output.
A laser drive control circuit for detecting laser power as a function of a control signal having variable duty cycle, said circuit comprising a counter, an oscillator and a timing circuit, said oscillator producing at an output periodic pulses at a frequency that is a predetermined multiple of the control signal frequency, said counter having a count input connected to said oscillator output to count the number of said oscillator pulses, said counter also having an inhibit input activated by the control signal, said counter being in a count mode during one portion of the control signal and being in a no-count mode during another portion of the control signal;
A method for determining the duty cycle of a control signal comprising the steps of:
Dependencies are inferred from the claim text.