Abstract: An instrument which provides a measurement of the frequency and power of a microwave signal supplied to an input port of the instrument. The instrument includes: a resistive device which divides the microwave signal supplied into first and second microwave divisions thereof; a frequency counter which measures the frequency of the first microwave division, thereby providing the measurement of the frequency of the microwave signal supplied; and a power sensor and power meter combination which measures the power of the second microwave division. The power sensor and meter combination makes a calibration correction dependent on the frequency measured by the frequency counter to its power measurement, thereby providing the measurement of the power of the microwave signal supplied.

Abstract: Disclosed is a Device Under Test (DUT) fault detection and location circuit. A first circuit port is connected to the DUT for fault detection and location. A signal source for generating a series of signals across the operating frequency range of the DUT is connected to a second circuit port. A divider divides each signal generated by the source so as to provide first and second fractions of the signal, the second fraction passing to the device under test. A fault detection section provides a DUT fault detection voltage for each respective frequency. The circuit also has a branch including an impedance section and a fault location section. The branch receives the first fraction, and the fault location section provides a DUT fault location voltage for each respective frequency.

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: An attenuator incorporates a matched circuit which directs a portion of the input power to a power detector (25). In response to the power level reaching a threshold value an actutor breaks the circuit through the attenuator to provide reverse power protection.

Abstract: In many microwave applications poor repeatability of results is often caused by differences in the quality of the coaxial connections. This invention overcomes the problem by ensuring more uniform connection by providing two mechanical connecting means radially separated from each other and coaxial with a central conducting means being connected, thus ensuring precise alignment of the two conductors.

Abstract: A test arrangement for testing high frequency electrical devices consisting of two 6-port reflectometers which are both connected to a device under test. In order to calibrate the test arrangement, an arbitrary termination generator is connected to each test port while its test signal represents a reflectivity coefficient of greater than unity, so that it simulates active devices as well as passive ones.

Abstract: A test arrangement for testing high frequency electrical devices consists of two 6-port reflectometers which are both connected to a device under test. As well as being applied to the device under test, a reference sample of an excitation signal is routed to both 6-port reflectometers simultaneously. The test arrangement is capable of very wide operation and is able to fully characterize the electrical properties of a device.

Abstract: A six-port reflectometer has first and second directional couplers, a first waveguide and a third directional coupler providing a series connection from a source to a test device. The first coupler is connected to two detectors. The second coupler is connected to a third detector and to a fourth waveguide having two ports connected via a waveguide and a further port connected to an absorber. The third coupler is connected to a detector and a reflector. The second waveguide and the reflector receive radiation coupled by the second and third couplers respectively. The third and fourth couplers provide equivalent transmission paths. Equal path lengths are traversed by signals leaving the second coupler and returning to it from the reflector and the fourth coupler respectively. With broad-band couplers and waveguides, this arrangement gives broad-band performance.