Low supply voltage frequency multiplier with common base transistor amplifier
First Claim
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1. In a circuit for generating an output signal having a frequency equal to a multiple of the frequency of an input signal applied thereto, said circuit being of the type including a zero-crossing detector for providing a signal having frequency components at harmonics of said input signal frequency, and a filter for passing only predetermined ones of said harmonics, the improvement wherein:
- said zero-crossing detector comprises;
first and second transistors, each having first and second electrodes defining a conduction path therebetween, and a control electrode, current flow through said conduction path being in accordance with the voltage difference between said control electrode and said second electrode;
said input signal being applied to said first transistor control electrode;
said first transistor first electrode being AC bypassed to ground potential to prevent thereby feedback between said first transistor first and control electrodes;
said first and second transistor second electrodes being coupled to a common node;
said second transistor control electrode being AC coupled to ground potential; and
said second transistor first electrode being coupled to said filter, to provide for, thereby, operation from relatively low supply voltages of said circuit at frequencies in the VHF range.
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Abstract
A frequency multiplier circuit utilizing a zero-crossing detector for producing a square wave at the frenquency of the input signal to generate harmonics of the input frequency. The square wave is filtered to generate a signal of a predetermined harmonic.
111 Citations
24 Claims
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1. In a circuit for generating an output signal having a frequency equal to a multiple of the frequency of an input signal applied thereto, said circuit being of the type including a zero-crossing detector for providing a signal having frequency components at harmonics of said input signal frequency, and a filter for passing only predetermined ones of said harmonics, the improvement wherein:
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said zero-crossing detector comprises; first and second transistors, each having first and second electrodes defining a conduction path therebetween, and a control electrode, current flow through said conduction path being in accordance with the voltage difference between said control electrode and said second electrode; said input signal being applied to said first transistor control electrode; said first transistor first electrode being AC bypassed to ground potential to prevent thereby feedback between said first transistor first and control electrodes; said first and second transistor second electrodes being coupled to a common node; said second transistor control electrode being AC coupled to ground potential; and said second transistor first electrode being coupled to said filter, to provide for, thereby, operation from relatively low supply voltages of said circuit at frequencies in the VHF range. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A circuit for generating an output signal having a frequency equal to a predetermined multiple of the frequency of an input signal applied thereto, said circuit being capable of generating said output signal in the VHF range and comprising:
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first and second transistors, each having first and second electrodes defining a conductor path therebetween, and a control electrode, current flow through said conduction path being in accordance with the difference in potential between said second and control electrodes; said first transistor being connected in a common second electrode manner with respect to said input signal, and being receptive of a signal indicative of said input signal at the control electrode thereof; said second transistor being connected in a common control electrode manner with respect to said input signals, said second transistor second electrode being coupled to the first transistor second electrode; and a filter circuit, responsive to signals from said second transistor first electrode, for passing only signals having frequencies within predetermined limits from said multiple frequency. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. In a circuit for generating an output signal having a frequency equal to a predetermined multiple of the frequency of an input signal applied thereto, comprising:
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first and second and third transistors, each having first and second electrodes defining a conduction path therebetween, and a control electrode, current flow through said conduction path being in accordance with the voltage difference between said control electrode and said second electrode; said input signal being applied to said first transistor control electrode, said first and second transistor second electrodes being coupled to a common node, said second transistor control electrode being AC coupled to ground potential; a differentiator circuit responsive to signals from said second transistor first electrode; and a filter circuit, responsive to signals from said differentiator circuit for passing only signals having frequencies within predetermined limits of said predetermined multiple. - View Dependent Claims (18, 19, 20)
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21. A circuit for generating an output signal having a frequency equal to a predetermined multiple of the frequency of the input signal applied thereto comprising:
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a differential transistor pair current switch, responsive to zero-crossings in said input signal, for passing current alternately to one of two paths; a common base amplifier circuit, responsive to current in one of said alternate current paths; a filter circuit, responsive to signals from said amplifier circuit, for passing only signals having frequencies within predetermined limits of said predetermined multiple frequency. - View Dependent Claims (22, 23, 24)
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Specification