# US 5,703,509 A · Frequency multiplier circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,509 A - Document ID: US5703509A - Status: Granted - Kind: A - Application number: 08/696,622 - Filed: 1996-08-14 - Granted: 1997-12-30 - Earliest claimed: 1995-08-14 - Assignees: NEC Corporation - Inventors: Masaru Hirata - Web page: https://patentgrep.com/patent/US5703509A ## CPC - H03B 19/00: Generation of oscillations by non-regenerative frequency multiplication or division of a signal from a separate source (transference of modulation from one carrier to another H03D7/00) - H03D 7/1433: {using bipolar transistors (H03D7/145 takes precedence)} - H03D 7/1458: {Double balanced arrangements, i.e. where both input signals are differential} - H03D 2200/0047: Offset of DC voltage or frequency - H03B: GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (generators adapted for electrophonic musical instruments G10H; masers or lasers H01S; generation of oscillations in plasma H05H) - H03D: DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER (masers, lasers H01S; circuits capable of acting both as modulator and demodulator H03C; details applicable to both modulators and frequency-changers H03C; demodulating pulses H03K9/00; transforming types of pulse modulation H03K11/00; coding, decoding or code conversion, in general H03M; repeater stations H04B7/14; demodulators adapted for AC systems of digital information transmission H04L27/00; synchronous demodulators adapted for colour television H04N9/66) ## Abstract A frequency multiplier circuit that needs no coupling capacitors and no input bias circuits for a next-stage circuit, which includes a phase-shifted signal generator, first and second differential amplifiers, and a multiplier. The phase-shifted signal generator receives an initial input signal and generates first and second output signals whose phases are shifted by 90.degree. with each other. The first differential amplifier amplifies the first output signal to output a first positive-phase output signal and a first negative-phase output signal. The second differential amplifier amplifies the second output signal to output a second positive-phase output signal and a second negative-phase output signal. The multiplier multiplies the first and second positive-phase output signals to output a third positive-phase output signal as a positive-phase output of the frequency multiplier circuit. At the same time, it multiplies the first and second negative-phase output signals to output a third negative-phase output signal as a negative-phase output of the frequency multiplier circuit. Each of the third positive- and negative-phase output signals has a doubled frequency of the initial input signal and substantially the same dc offset voltage. ## Claims ### Claim 1 A frequency multiplier circuit comprising: a phase-shifted signal generator for receiving an initial input signal to generate first and second output signals whose phases are shifted by 90.degree. with each other; a first differential amplifier for receiving said first output signal to amplify said first output signal and for outputting a first positive-phase output signal and a first negative-phase output signal; a second differential amplifier for receiving said second output signal to amplify said second output signal and for outputting a second positive-phase output signal and a second negative-phase output signal; a multiplier for receiving said first and second positive-phase output signals to multiply said first and second positive-phase output signals, outputting a third positive-phase output signal as a positive-phase output of said frequency multiplier circuit, receiving said first and second negative-phase output signals to multiply said first and second negative-phase output signals, and outputting a third negative-phase output signal as a negative-phase output of said frequency multiplier circuit; wherein each of said third positive- and negative-phase output signals has a doubled frequency of said initial input signal and substantially the same dc offset voltage. ### Claim 2 (depends on 1) The circuit as claimed in claim 1, wherein said phase-shifted signal generator includes an integrator and a differentiator connected in parallel. ### Claim 3 (depends on 2) The circuit as claimed in claim 2, wherein said integrator has a first resistor and a first capacitor and said differentiator includes a second resistor and a second capacitor; and wherein said first and second resistors have the same resistance value, and said first and second capacitors have the same capacitance value. ### Claim 4 A frequency multiplier circuit comprising: a differential amplifier for receiving an initial input signal to amplify said initial input signal and for outputting a first positive-phase output signal and a first negative-phase output signal; a first phase-shifted signal generator for receiving said first positive-phase output signal to generate first and second output signals whose phases are shifted by 90.degree. with each other; a second phase-shifted signal generator for receiving said first negative-phase output signal to generate third and fourth output signals whose phases are shifted by 90.degree. with each other; and a multiplier for receiving said first and second output signals to multiply said first and second output signals, outputting a second positive-phase output signal as a positive-phase output of said frequency multiplier circuit, receiving said third and fourth output signals to multiply said third and fourth output signals, and outputting a second negative-phase output signal as a negative-phase output of said frequency multiplier circuits, wherein each of said second positive- and negative-phase output signals has a doubled frequency of said initial input signal and substantially the same dc offset voltage. ### Claim 5 (depends on 4) The circuit as claimed in claim 4, wherein each of said phase-shifted signal generators includes an integrator and a differentiator connected in parallel. ### Claim 6 (depends on 5) The circuit as claimed in claim 5, wherein said integrator has a first resistor and a first capacitor and said differentiator includes a second resistor and a second capacitor; and wherein said first and second resistors have the same resistance value, and said first and second capacitors have the same capacitance value.