Low supply voltage frequency multiplier with common base transistor amplifier
OwnerRafi Arakelian, Michael M. Driscollinventors
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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.
Claims24
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.
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:
- 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.
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:
- 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.
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:
- 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.
Dependencies are inferred from the claim text.