摘要:
An improved microwave oscillator wherein the oscillator includes a resonator assembly provided with a movable resonator member for varying the frequency response of the oscillator and which further includes a transistor, the improvement including means for varying the electrical coupling between a lead of the transistor and the resonator assembly to provide optimum coupling between the transistor lead and the resonator assembly for maximum power output; means for compensating for variations in frequency response of the oscillator upon different transistors being positioned different distances from the resonator assembly; coupling means electrically associated with the transistor to assure proper coupling between the transistor and the resonator assembly at the low frequencies; means for providing additional feedback to the transistor to assure sufficient feedback to sustain low frequency oscillation of the transistor which is typically chosen and designed for high frequency oscillation; and a flexible linkage interconnected between the resonator movable member and the apparatus for moving the resonator movable member whereby any lateral misalignment between structural members and apertures is compensated for.
摘要:
An oscillator circuit suitable for use in a local oscillator of a tuner of a television receiver set. A feedback circuit comprised of a feedback capacitor (17) is connected between a junction of a tuning diode (10) and a correcting capacitor (11) connected in series therewith and the emitter of an oscillation transistor (1). Oscillation voltage developing across the correcting capacitor is fedback to the emitter of the oscillation transistor through the feedback capacitor. When the tuning diode is conditioned to have a large capacitance value, a large oscillation voltage is fedback to the transistor through the feedback capacitor whereas when the tuning diode is conditioned to have a small capacitance value, a small oscillation voltage is fedback to the transistor through the feedback capacitor. The oscillator circuit continues to oscillate stably over a wide frequency range whenever the tuning diode changes from the small capacitance value to the large capacitance value or vice versa.
摘要:
Problems associated with compromise, fixed base inductances in negative resistance oscillators are overcome by use of an electronically tunable base network. Parameters such as phase noise and output power can thereby be optimized over a wide range of operating conditions. The disclosure is illustrated with reference to a 500-1000 Mhz voltage controlled oscillator employing base-tuning varactors that are slaved to the VCO's tuning signal.
摘要:
An oscillator providing predictable oscillator modulation sensitivity includes an amplifier and a feedback circuit disposed about the amplifier. The feedback circuit includes a resonator having a first port and a second port and a voltage-controlled phase shifter having an input port, an output port and a control port, the input port of the voltage-controlled phase shifter connected to the output port of the amplifier and the output port of the voltage-controlled phase shifter coupled to a port of the resonator. The oscillator further includes a circuit, responsive to signals from the output of the voltage-controlled phase shifter and the first port of the resonator, to provide a control signal to the control port of the voltage-controlled phase shifter for degenerating low frequency FM noise arising within the amplifier.
摘要:
An oscillator including a resonator with at least one first tuneable element, with which a resonant frequency of the resonator can be varied. The oscillator further includes an amplifier, which provides an amplification element, connected to the resonator at a coupling position. The amplifier provides a second tuneable element, by which a complex resistance, which the amplifier provides at the coupling position, is variable in a frequency-dependent manner.
摘要:
An oscillator including a resonator with at least one first tuneable element, with which a resonant frequency of the resonator can be varied. The oscillator further includes an amplifier, which provides an amplification element, connected to the resonator at a coupling position. The amplifier provides a second tuneable element, by which a complex resistance, which the amplifier provides at the coupling position, is variable in a frequency-dependent manner.
摘要:
A voltage-controlled oscillator (VCO) circuit includes first, second, third, and fourth transistors, each with a first terminal, a second terminal, and a control terminal. The first terminal of the first transistor communicates with the first terminal of the second transistor. The control terminals of the third and fourth transistors communicate with the second terminals of the first and second transistors, respectively. The first terminals of the third and fourth transistors communicate with the control terminals of the first and second transistors, respectively. First ends of first and second capacitances communicate with the second terminals of the first and second transistors, respectively. Second ends of the first and second capacitances communicate with the control terminals of the first and second transistors, respectively.
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 voltage-controlled oscillator (VCO) circuit includes first, second, third, and fourth transistors, wherein said third and fourth transistors bias the second and first transistors, respectively. First and second capacitances communicate with the first, second, third, and fourth transistors. A first input receives a first capacitance adjustment signal. At least one second input receives a second capacitance adjustment signal. The first capacitance has a first end connected to he first input and the third transistor. The second capacitance has a first end connected to the second input and the fourth transistor.
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.