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 synchronization 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 synchronization 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 correponding 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:
A broad band high frequency sweep generator is disclosed wherein the operating modes and critical frequencies are selected by pushbutton actuated switches. The switches are interconnected in order to insure that each mode discretely controls operation of the generator and the critical frequencies required for any particular mode only are selected.
Abstract:
A method and apparatus for testing the response of a device to RF signals of different frequency generated by apparatus comprising an RF signal generator (26) having at least two modes of operation which entails at least one source change between one mode and the other comprising the step of detecting unwanted electrical noise in the signal transmitted by the device under test by means of a detector (334), amplifiers (336, 338) and compensating for said unwanted electrical noise by signals from a DAC (340), and amplifier (342, 344, 346 and 336) during each mode of operation of the generator. Different compensation is required for the different modes of operation of the RF source, and appropriate compensation is selected by reference to the source in use at the time.
Abstract:
YIG oscillator apparatus (230) having both an FET-based YIG oscillator circuit (10) and a bipolar transistor based YIG oscillator circuit (110) inside a single magnetic structure (200). Both YIG spheres (12, 112) are disposed in the single air gap (220) of the magnetic structure, which is defined by a pole piece (210) which is tapered to an elongated pole surface (214) which is only slightly larger than necessary to cover both YIG spheres.
Abstract:
A tuned oscillator is disclosed which consists of an active element (1) for oscillation, a ferrimagnetic resonant element (2) connected to part of feedback of the active element (1), and a matching circuit (3) connected to the active element (1). The matching circuit (3) is designed to reflect the fundamental wave produced by the ferrimagnetic resonant element (2) and active element (1) and pass the second harmonic wave. Consequently, the magnetic circuit has its load reduced in applying a D.C. magnetic field necessary for frequency tuning to the ferrimagnetic resonance element (2).
Abstract:
A tuned oscillator comprises an active element such as an FET (1) for oscillation and an YIG thin film ferrimagnetic resonator (2) connected to the FET (1) as part of a feedback circuit for the FET (1). The YIG thin film resonator (2) includes an YIG disc (2a) and has a bias magnetic field (H) applied perpendicular to a surface of the YIG disc (2a) to set the resonant frequency. The magnetic field (H) is generated both by a permanent magnet (4c) for providing a fixed component of the field and also by a coil (4b) for providing a variable component of the field. The resonant frequency is stabilised by a PLL circuit (5) connected to an output of the oscillator and with a feedback connection to the coil (4b). Since the YIG thin film tuned oscillator has a high Q value, high quality communication signal processing can be achieved. The YIG tuned oscillator may be used as a local oscillator for a transceiver.
Abstract:
PURPOSE: To set a sweep start and a sweep end frequency of a frequency sweep range in advance and to set accurately the set frequency range, by changing respectively an attenuation of the 1st and the 2nd set means. CONSTITUTION: The sweep end voltage is set to an optional value in the range of 0∼+E by changing the attenuation of the 1st set means 3. Further, the sweep start voltage is set to an optional value in the range of 0∼+E by changing the attenuation of the 2nd set means 3. Thus, the sweep start and the sweep end frequency of a voltage controlled oscillator VCO7 are set accurately to an optional frequency of the sweep range of the VCO7 by setting suitably the set conditions of the 1st and the 2nd set means 3, 4. COPYRIGHT: (C)1984,JPO&Japio
Abstract:
Three embodiments of a tunable ferroelectric transmitting system are included. Each embodiment includes a tunable oscillator and a tunable antenna. Two embodiments include a negative resistance diode, the frequency of oscillation being controlled by a single crystal tunable ferroelectric resonator. The third embodiment uses a transistor. The tunable antenna is made of a single crystal tunable ferroeletric resonator. All conducting depositions are made of films of a high Tc superconducting material.