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US 4,490,653 AGranted
Deflection systems and ramp generators therefor
AssigneeTektronix, Inc.
InventorHarold W. Olmstead
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AssigneeTektronix, Inc.
InventorHarold W. Olmstead
Estimating the term…
A ramp generator comprises an integrating capacitor and a current source connected to the capacitor to charge the capacitor and thereby generate a ramp signal. A switching device is connected to the capacitor and is operative to discharge the capacitor periodically in response to a periodic control signal applied to a control terminal of the switching device. A comparator has a first input terminal connected to a peak detector, which detects the peak value of the ramp signal, and a second input terminal connected to receive a reference voltage. The comparator compares the peak value of the ramp signal and the reference voltage and is connected to the current source to control the rate of supply of current to the capacitor in response to the comparison result so as to maintain a predetermined relationship between the amplitude of the ramp signal and the reference voltage, independently of the frequency of the control signal.
A ramp generator comprising an integrating capacitor, current source means, connected to the capacitor to charge the capacitor and thereby generate a ramp signal, a switching device connected to said capacitor and having a control terminal and operative to discharge said capacitor periodically in response to a periodic control signal applied to said control terminal, a peak detector connected to the capacitor for detecting the peak value of the ramp signal, a comparator having a first input terminal connected to the peak detector and a second input terminal for application of a reference voltage to the comparator, said comparator being operative to compare said peak value and said reference voltage and being connected to said current source means to control the rate of supply of current to the capacitor in response to the comparison result so as to maintain a predetermined relationship between the amplitude of the ramp signal and said reference voltage, independently of the frequency of the control signal.
A resonant deflection system for a raster scan CRT display apparatus including a CRT having a face, means for generating an electron beam which is incident on the face of the CRT, and deflection coil means for generating a magnetic field to deflect the point of incidence of the electron beam over the face of the CRT, said deflection system comprising a ramp generator which has a control terminal for receiving a periodic control signal and a reference voltage terminal for receiving a reference voltage and is operative to generate a ramp signal having an amplitude which bears a predetermined relationship to said reference voltage and is substantially independent of the frequency of the periodic control signal, said ramp signal having a frequency which bears a predetermined relationship to the frequency of the periodic control signal, and the deflection system further comprising correction circuitry connected to receive the ramp signal from the ramp generator and provide an output voltage conforming to a desired waveform, and a resonant deflection current generator connected to receive said output voltage and generate in response thereto a deflection current for energizing the deflection coil means, said deflection current generator also having an input for receiving a synchronization signal and having an output for providing a retrace blanking signal derived from the synchronization signal and which is applied to the control terminal of the ramp generator as said periodic control signal.
A ramp generator comprising an integrating capacitor, current source means connected to the capacitor to charge the capacitor and thereby generate a ramp signal, a switching device connected to said capacitor and having a control terminal and operative to discharge said capacitor periodically in response to a periodic control signal applied to said control terminal, and feedback means connected between the capacitor and the current source means for controlling the rate of supply of current to the capacitor by the current source means in order to maintain a predetermined relationship between the amplitude of the ramp signal and said reference voltage, independently of the frequency of the control signal.
Dependencies are inferred from the claim text.