摘要:
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 frequency synthesizer can interpolate the step size of the first signal generator with half the number of steps. While, heretofore, the 100 MHz step size was interpolated with Fq=0, 10, 20, 30, 40 and 50 MHz, Fq=0, 20, 40 MHz interpolation is made possible. This permits the synthesis of 580 MHz to 1280 MHz. In this case, however, the minimum difference between the sum and difference frequencies from the first and second signal generators is 40 MHz and the lowest frequency is 20 MHz. Thus, depending on mixer isolation, the spurious measures become difficult. The frequency synthesizer of the present invention pays attention to the fact that 20 MHz step signals can be synthesized at frequencies which are integral multiples of Fq (multiples of 0 and 5 are excluded). When two-fold Fq is used, the minimum difference between the sum and difference frequencies output from a mixer is 80 MHz and the lowest used frequency is 40 MHz. The spurious measures by a PLL circuit becomes easy. A frequency detector forces the free-running frequency of a VCO included the PLL circuit. Control Data P and Q to the first and second signal generators are supplied from a control section based on data Fi set by a frequency setting section.
摘要:
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 divider in a PLL circuit constituted by a variable frequency oscillator 4, a frequency divider 6, and a phase detector 2. The arithmetic circuit includes a plurality of series-connected cumulative adders 22 which include a first cumulative adder that receives a rational number defined by an integer value and a decimal value, an integer value extraction circuit 23 for extracting an integer value from the output value of the cumulative adder of the final stage, and a delay circuit 24 for outputting the integer value extracted by the integer value extraction circuit to the frequency divider as the frequency division ratio, and outputting the integer value to the respective cumulative adders as a feedback value. Each cumulative adder adds a value calculated by itself in the previous clock period to the input rational number or the output value from the cumulative adder of the previous stage, and subtracts the feedback value from the delay circuit therefrom, thus outputting the calculated value.
摘要:
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..sub.2 t+.psi.) . . . Asin(.omega..sub.K t+.psi.), which are in phase at time point (t=0), in response to the output signal of the first reference frequency generator. A switching circuit selectively switches the output signals from the plurality of said second reference frequency generators. A timing pulse generator generates timing pulses to operate said switching circuit at time T as given by .vertline..omega..sub.i+1 T-.omega..sub.i T.vertline.=2l.pi. (l:integer) where i=1, 2 . . . K-1.
摘要:
A power sensing and switching circuit, using voltage and current sensors, integrated circuits and logic gates that detects reverse power flow, from reactive loads, non-linear loads or dispersed electrical generators, and mitigates reverse power flow by functioning as a power factor correction device and by diverting the reverse power flow as recycled power to storage, local usage, or remote usage via a recovery line that mitigates distribution grid instability and speeds up the growth of dispersed electrical generators.
摘要:
A power sensing and switching circuit, using voltage and current sensors, integrated circuits and logic gates that detects reverse power flow, from reactive loads, non-linear loads or dispersed electrical generators, and mitigates reverse power flow by functioning as a power factor correction device and by diverting the reverse power flow as recycled power to storage, local usage, or remote usage via a recovery line that mitigates distribution grid instability and speeds up the growth of dispersed electrical generators.
摘要:
A power sensing and switching circuit, using voltage and current sensors, integrated circuits and logic gates that detects reverse power flow, from reactive loads, non-linear loads or dispersed electrical generators, and mitigates reverse power flow by functioning as a power factor correction device and by diverting the reverse power flow as recycled power to storage, local usage, or remote usage via a recovery line that mitigates distribution grid instability and speeds up the growth of dispersed electrical generators.
摘要:
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 outputting an output error signal; an integrator for integrating the output error signal from the phase detector to extract a direct current variable component contained in the output error signal, the integrator having a first cutoff frequency; and a loop filter for feeding the direct current variable component from the integrator to the voltage controlled oscillator as the control signal to synchronize the output signal from the voltage controlled oscillator with the reference signal. An alternate current coupling circuit is provided for adding only an alternate current component contained in the output error signal from the phase detector to the control signal for feeding to the voltage controlled oscillator; and a compensating circuit is inserted in an alternate current signal path of the alternate current coupling circuit. The compensating circuit is inserted in an alternate current signal path of the alternate current coupling circuit. The compensating circuit has a second cutoff frequency exceeding the first cutoff frequency of the integrator, so that a wide band characteristic is obtained, and SSB phase noise suppression is improved.
摘要:
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 output, the input being connected to the resonant circuit in order to receive a resonant output therefrom. A variable capacitance ratio circuit, having a second variable capacitance diode and at least one capacitor, is connected in a positive feedback manner, between the input and the output of said active circuit means in order to oscillate the active element of the active circuit at a resonant frequency of the resonant circuit, between the input and the output of the active circuit. A variable controller is provided for changing a resonant frequency of the resonant circuit, to thereby apply a control voltage to the first and second variable capacitance diodes and to control a capacitance ratio between the at least one capacitor and the second variable capacitance diode in the variable capacitance ratio circuit, so that an oscillator frequency of the active element can be changed substantially linearly over a wide bandwidth of no less than one octachord in accordance with a variation in the control voltage, to thereby retain the amount of positive feedback at a predetermined level against the oscillator frequency of the active circuit.
摘要:
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 and the coefficient p is an integer); and a second signal generator responsive to the control section for selectively outputting one of frequencies whose frequencies are represented by Fq=b.times..vertline.Q.vertline..times..DELTA.F (where the coefficient b is a positive integer exclusive of integral multiples of prime factors into which a is resolved, and the coefficient Q is an integer and satisfying the expression: .vertline.Q.vertline..ltoreq.(a-1)/2. A mixer mixes a frequency signal Fp from the first signal generator and a frequency signal Fq from the second signal generator; and a frequency selecting circuit selects either of frequency signals .vertline.FP-Fq.vertline. or Fp+Fq output from the mixer. The control section determines the values of P and Q satisfying the following expresion P=T+(S-b.times.Q)/a on the basis of a desired frequency signal Fi=m.times..DELTA.F, a coefficient m=0, 1, 2, ..n set in predetermined frequency .DELTA.F; and quotient T and remainder s of m/a to cause each of the first and second signal generators to output a predetermined frequency and the frequency selecting circuit to select one of the frequency signals .vertline.Fp-Fq.vertline. and Fp+Fq that corresponds to the frequency signal Fi.