Abstract:
Apparatus and methods are disclosed related to an oscillator that includes a sustaining amplifier. One such apparatus includes a resonant circuit configured to operate at a resonant frequency, a sustaining amplifier, and a passive impedance network. The resonant circuit can have a first terminal and a second terminal. The sustaining amplifier can include at least a first switch configured to drive the first terminal of the resonant circuit in response to an input at a first control terminal of the first switch. The passive impedance network can be configured to pass a bias to the first control terminal, such as a gate of a field effect transistor, of the first switch. The passive impedance network can be electrically coupled to the second terminal of the resonant circuit and can include at least one inductor.
Abstract:
An electronic oscillator of the Colpitts type with an amplifying element and a tank circuit. The tank circuit includes a parallel tuned resonant circuit, a series tuned resonant circuit and a switching circuit that selectively connects one of the resonant circuits to the tank circuit. The oscillator operates at a first frequency in the parallel tuned mode and a second frequency that is substantially twice the first frequency in the series tuned mode.
Abstract:
A monolithic high frequency voltage controlled oscillator trimming circuit includes a plurality of capacitance loops selectively connected between a first and second differential input of a voltage oscillator active network. A plurality of diodes, connected in series with the respective plurality of capacitance loops, selectively connect respective capacitance loops between the first and second differential input when forward biased. In a similar fashion, the plurality of diodes selectively disconnect the respective capacitance loops from the first and second differential input when reverse biased. A controller applies a forward biasing voltage to the diode of the selected capacitance loop to connect the capacitance loop to the active network of the voltage controlled oscillator and applies a reverse biasing voltage to the diode of the selected capacitance loop to disconnect the capacitance loop from the active network. The diodes used in the capacitance loops form a switch operable at high frequencies and are formed from a bipolar complementary metal oxide semiconductor electro-static discharge protection diode.
Abstract:
Apparatus and methods are also disclosed related to an oscillator that includes a switching network configured to tune a resonant frequency of a resonant circuit. One such apparatus includes a switching network having a circuit element, such as a capacitor, that can be selectively coupled to the resonant circuit by a switch, such as a field effect transistor. For instance, the switch can electrically couple to circuit element to the resonant circuit when on and not electrically couple the circuit element to the resonant circuit when off. An active circuit can assert a high impedance on an intermediate node between the switch and the circuit element when the switch is off.
Abstract:
A voltage controlled oscillator comprises an oscillation transistor, a varactor diode, a resonance circuit which is coupled to the oscillation transistor, and a switching diode which changes over a resonance frequency of the resonance circuit, wherein the resonance circuit includes a first strip conductor which is served for grounding a cathode of the varactor diode in terms of direct current and a second strip conductor which is served for coupling a cathode of the varactor diode with the oscillation transistor, the switching diode is connected to the first strip conductor in parallel in terms of high frequency and has a cathode thereof grounded, and a control voltage which is served for changing a capacitive value of the varactor diode is applied to a connection point between the cathode of the varactor diode and the second strip conductor through a choke inductor.
Abstract:
In a three-band switching oscillator, a switching circuit is provided to switch the operating conditions of a first and second voltage-controlled oscillator and to switch an oscillation frequency band of the first voltage-controlled oscillator. The switching circuit switches a first switch in accordance with a switching voltage inputted to a first switching terminal and switches an oscillation frequency band in accordance with a switching voltage inputted to a second switching terminal. Only when a high-level switching voltage is inputted to the second switching terminal, the second switch is placed into an open condition by a high-level switching voltage inputted to the first switching terminal and placed into a closed condition by a low-level switching voltage inputted thereto, and when a low-level switching voltage is inputted to the second switching terminal, the second switch is placed into the open condition irrespective of the switching voltage inputted to the first switching terminal.
Abstract:
A voltage-controlled oscillator and a method capable of precisely adjusting a frequency shift amount are provided irrespective of a fluctuation in characteristics of elements such as a strip-line. A center tap 19 is formed in a strip-line 16 of a resonator. A switching element 20 is connected to the center tap 19, and this switching element 20 is turned ON, so that the center tap is shortcircuited to the ground so as to vary the oscillating frequency. A slit A1 is conducted in the vicinity of the center tap 19 along the strip-line 16 and directed toward a shortcircuited end 17 of the strip-line, so that a frequency shift amount is adjusted. Also, a slit B1 is conducted in the vicinity of the shortcircuited end 17 along the strip-line 16 and directed toward the center tap 19, so that a frequency shift amount is adjusted. Also, trimming points are provided on the side of a hot terminal 18 from the center tap 19, and also provided on the side of the shortcircuited end 17 from the center tap 19, and further a slit is conducted along an intersecting direction of the strip-line 16, so that a shift amount is adjusted.
Abstract:
YIG oscillator apparatus comprises both an FET-based YIG oscillator circuit and a bipolar transistor-based YIG oscillator circuit inside a single magnetic structure. Both YIG spheres are disposed in the single air gap of the magnetic structure, which is defined by a pole piece which is tapered to an elongated pole surface which is only slightly larger than necessary to cover both YIG spheres. A band reject filter is included inside the housing for rejecting second harmonics of desired oscillation frequencies only.
Abstract:
YIG oscillator apparatus comprises both an FET-based YIG oscillator circuit and a bipolar transistor-based YIG oscillator circuit inside a single magnetic structure. Both YIG spheres are disposed in the single air gap of the magnetic structure, which is defined by a pole piece which is tapered to an elongated pole surface which is only slightly larger than necessary to cover both YIG spheres.