1
Hatsuo Motoyama, Tetsuo Igawa: Direct frequency synthesizer which is step-wise variable and has phase continuity and phase reproducibility when switching frequencies. Anritsu Electric Company, Frishauf Holtz Goodman & Woodward, April 21, 1987: US04659999 (27 worldwide citation)

In a signal generator based on Direct Frequency Synthesis, a first reference frequency generator generates a signal of a reference frequency. A plurality of second reference frequency generators, respectively, generates K signals with different frequencies Asin(.omega..sub.1 t+.psi.), Asin(.omega..s ...


2
Hiroshi Saeki, Hatsuo Motoyama: Advanced phase locked loop circuit. Anritsu Corporation, Frishauf Holtz Goodman & Woodward, October 19, 1993: US05254955 (26 worldwide citation)

A PLL circuit comprises a voltage controlled oscillator responsive to a control signal to output an output signal having a variable oscillation frequency; a phase detector for making a phase comparison between the output signal from the voltage controlled oscillator and a reference signal, and for o ...


3
Norihiro Akiyama, Hirokazu Yanagawa, Hatsuo Motoyama: Rational frequency division device and frequency synthesizer using the same. Anritsu Corporation, Frishauf Holtz Goodman Langer & Chick, September 15, 1998: US05808493 (6 worldwide citation)

A rational frequency division device eliminates spurious components by a simple arrangement and can set a broad frequency modulation range. A frequency synthesizer using the rational frequency division device includes an arithmetic circuit, which outputs the frequency division ratio to a frequency d ...


4
Hiroshi Saeki, Hatsuo Motoyama: Voltage controlled oscillator with controlled capacitance ratio in positive feedback loop to broaden bandwidth. Anritsu Corporation, Frishauf Holtz Goodman & Woodward, November 3, 1992: US05160902 (5 worldwide citation)

A voltage controlled oscillator comprises a resonant circuit having at least a coil and a first variable capacitance diode, and resonating within predetermined variable frequency ranges; and an active circuit having an input, an output, and an active element connected between the input and the outpu ...


5
Hiroshi Saeki, Hatsuo Motoyama: Frequency snythesizer for implementing generator of highly pure signals and circuit devices, such as VCQ, BLL and SG, used therein. Anritsu Corporation, Frishauf Holtz Goodman and Woodward, June 16, 1992: US05122763 (5 worldwide citation)

A frequency synthesizer includes a control section; a first signal generator responsive to the control section for selectively outputting one of frequency signals whose frequencies are represented by Fp=a.times..vertline.P.vertline..times..DELTA.F (where the coefficient a is a positive odd number an ...


6
Hiroshi Saeki, Hatsuo Motoyama: Frequency synthesizer for implementing generator of highly pure signals and circuit devices, such as VCO, PLL and SG used therein. Anritsu Corporation, Frishauf Holtz Goodman & Woodward, June 8, 1993: US05218313

To output desired high purity signals, a frequency synthesizer was made to synthesize reference signals from a first and second signal generators in the same frequency band as a desired frequency band. Thereby, the resolution of the frequency synthesizer becomes twice the step .DELTA.F. Also, the fr ...