Abstract:
For realizing a highly sensitive and favorably linear frequency modulator stably operating with a small-sized and readily manufactured arrangement, input and output strip electrodes are disposed in face on both ends of a ferri-magnetic film deposited on a magnetic substrate and applied with a DC magnetic field perpendicular thereto, a high frequency electro-magnetic wave being applied through the input electrode, so as to generate a magneto-static forward volume wave propagating through the magnetic film, the propagation phase of which is modulated in response to the intensity variation of the applied magnetic field modulated by a signal, so as to derive a frequency modulated electro-magnetic wave from the output electrode.
Abstract:
A resonant microwave isolator is described in which a diagonal slot is fod in the top conductor of a microstrip, a strip of ferromagnetic material is mounted over at least a portion of the slot and magnetic flux is established in the ferromagnetic material in a direction intersecting the slot.
Abstract:
Apparatus for allowing low noise and fast frequency switching of a ferri-resonant oscillator, such as YIG, that uses a coil to control output signal frequency by current level. The apparatus positions an active filter in parallel with the oscillator coil, which can be set to one of two impedance levels. A low impedance level provides low pass filtering of the current to the oscillator coil for low noise operation. A second high impedance level allows fast settling of transients during frequency changes. Once current levels have stabilized, the active filter can then be switched to low impedance mode without creating a significant transient. This facilitates fast frequency switching.
Abstract:
A swept synthesizer signal source provides a digital synchronization signal for accurate internal synchronization of events and for external synchronization of data taking and other operations to predetermined frequencies generated by an oscillator during a sweep. The digital synchronication signal includes a predetermined number of digital pulses, regardless of the sweep time. A ramp voltage which controls the oscillator is corrected during a calibration period to sweep between predetermined limits, thereby insuring that the ramp voltage is synchronized to the digital synchronication signal. The slope of the frequency versus time sweep is also corrected to further improve accuracy. A power level correction technique insures precision power leveling regardless of the sweep range. A table of correction/frequency pairs is entered into the instrument, and an interpolation algorithm is employed to determine corrections at frequencies corresponding to each synchronization pulse. The source can be used in a network analyzer system wherein the synchronization pulses are provided to a receiver to trigger data taking. Two or more sources can be interconnected to provide synchronized sweeps.
Abstract:
Microwave oscillator using magnetostatic surface or bulk waves which can be transmitted in a thin layer of magnetic material having two cavity resonators with coupled gratings of different equivalent lengths in such a way that the first is multimode and the second monomode in the reflection pass band of the gratings, the cavities being arranged in such a way that the second filters the modes transmitted in the first. Microwave signals are applied to one of the two cavities and the resonated waves are collected in the second cavity.
Abstract:
A microwave synthesiser comprising: a plurality of oscillator sources (1, 13, 3, 15, 5, 17, 7), each for generating signals over a range of frequencies, said ranges of frequencies together extending over a total range of frequencies generated; phase locked loops (19, 31, 83, 37, 38, 41, 81) for phase-locking any selected one of said oscillator sources (1, 13, 3, 15, 5, 17, 7) so that it generates signals of a frequency at which it is set; a single low harmonic modulator (21) for modulating the signals generated by the selected one of said oscillator sources (1, 13, 3, 15, 5, 17, 7), the modulated signals passing to an output (27) of said synthesiser; and at said output (27) elements (25, 29) for detecting the power of the signals at said output (27), the modulation by said single low harmonic modulator (21) being controlled in dependence on the detected power thereby to control the power of the signals at said output (27).
Abstract:
A very high frequency oscillator (4-22 GHz) including field effect transistor and first and second YIG sphere resonators whose reactant frequencies are displaced, which gives the oscillator a wide frequency range. The first YIG sphere is doubly coupled to the source and gate of the transistor, which gives the oscillator good linearity (.perspectiveto.10.sup.-3) over its frequency range. The second YIG sphere is coupled to the gate by a coupling wire which also couples to the first YIG sphere.
Abstract:
A stable, low noise voltage-to-current converter is provided to control the tuning current in YIG tuned devices such as YIG tuned transistor oscillators. The circuit provides stable tuning current which is substantially noise free.
Abstract:
A sweep voltage from a sweep voltage generator is provided to sweep start and stop adjusting means, the outputs of which are summed by a summing circuit and, by the summed output, the oscillation frequency of a voltage controller oscillator is controlled. The oscillation frequency of the voltage controlled oscillator and the output frequency of a reference signal generator set to a sweep start frequency are compared by comparing means. The output of the sweep voltage generator is put in a sweep start state and sweep start adjusting means is adjusted in accordance with the output of the comparing means, thereby to cause the oscillation frequency of the voltage controlled oscillator to agree with a set sweep start frequency. The output of the sweep voltage generator is put in a sweep stop state and sweep stop adjusting means is adjusted in accordance with the output of the comparing means, thereby to cause the oscillation frequency of the voltage controlled oscillator to agree with a set sweep stop frequency.
Abstract:
A controlled voltage yttrium iron garnet (YIG) resonator incorporates a clipping diode in order to maintain a constant output voltage. The clipping diode is connected either across an input or an output loop associated with the resonator. The resonator, as a result of its high Q characteristic, is insensitive to changes in capacitance of the clipping diode.