Abstract:
Circuits and methods for generating a pulse are provided. The generating can comprise receiving at least one trigger input signal with a pulse generating circuit; generating a voltage pulse having a duration less than the avalanche time of a transistor in response to at least a portion of the at least one trigger input signal with the pulse generating circuit; transmitting the voltage pulse from the pulse generating circuit to a terminal of the transistor, the transistor constructed and arranged to be operable in an avalanche mode; and outputting an avalanche pulse from at least one terminal of the transistor in response to the voltage pulse. In some embodiments, the pulse can be transmitted with an antenna in a radar system, and a return pulse can be received and processed.
Abstract:
A fast scanning voltage ramp generator including at least one chain of N two-pole avalanche transistors in series and a set of N+1 zener diodes in series between a high voltage power supply and ground, where N is an integer number≧2. A streak camera can utilize this type of generator.
Abstract:
This invention relates to a fast scanning voltage ramp generator comprising at least one chain of N two-pole avalanche transistors in series (T1-T8; T11-T18) and a set of Nnull1 zener diodes (D1-D9) in series between a high voltage power supply (HV) and the ground, where N is an integer number null2. This invention also relates to a streak camera using this type of generator.
Abstract:
A pulse-echo ranging system is described employing a microwave transducer head (100) providing an echo profile output signal which is largely compatible with receivers (204) and echo processing systems (206) designed for acoustic transducers. The transducer head employs novel microwave pulse generators (20a, 20b) each utilizing a microwave cavity (20a, 20b) excited by an avalanche discharge through a small signal diode (D2a, D2b) initiated by avalanche of a driver transistor (TR1a, TR1b) by a trigger pulse. Repeated pulse from one generator (2a) are transmitted by an antenna (12) towards a target, and return are mixed with pulses from the second generator (26) which are subject to a progressively swept delay relative to the transmitter pulses. The mixer output is applied to a tuned amplified (110) to extract components at an alias frequency related to the sweep rate of the delay relative to the transmitter frequency. The aliased signal is passed to a receiver (204) and echo processing system (206).
Abstract:
A fast voltage ramp generator comprises a chain of transistors connected collector to emitter in series, and biased to avalanched switching mode. A respective transformer secondary is connected to apply a switching pulse across the base emitter junction of each transistor of the chain to effect avalanche switching of the chain. The transformer secondaries are the secondaries of discrete transformers with respective primaries connected in series. The transformers are formed of ferrite beads having plated through holes constituting the secondaries of the transformers. The beads are threaded on an insulated conductor which constitutes the series connected primaries of the transformers.