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Typically, these fences are 2.4 metres (7 ft 10 in) tall and send high voltage electric pulses through the palisade at a frequency of 1 Hz (one pulse per second). Palisade electric fences are used in most countries, particularly where there is little vegetation to short-circuit the fence or where the costs of security personnel are high in ...
A pet fence or radio fence, is an electronic system designed to keep a pet or other domestic animal within a set of predefined boundaries without the use of a physical barrier. A mild electric shock is delivered by an electronic collar if its warning sound is ignored.
Pulse generators may use digital techniques, analog techniques, or a combination of both techniques to form the output pulses. For example, the pulse repetition rate and duration may be digitally controlled but the pulse amplitude and rise and fall times may be determined by analog circuitry in the output stage of the pulse generator.
The pulse-repetition frequency (PRF) is the number of pulses of a repeating signal in a specific time unit. The term is used within a number of technical disciplines, notably radar. In radar, a radio signal of a particular carrier frequency is turned on and off; the term "frequency" refers to the carrier, while the PRF refers to the number of ...
The shape of the pulse is often a half cycle sinusoid. [2] For longer cables, wider pulse widths are used. Fast rise time steps are also used. Instead of looking for the reflection of a complete pulse, the instrument is concerned with the rising edge, which can be very fast. [3] A 1970s technology TDR used steps with a rise time of 25 ps. [4 ...
The spectral shear is typically generated by sum-frequency mixing the test pulse with two different quasi-monochromatic frequencies (usually derived by chirping a copy of the pulse itself), although it can also be achieved by spectral filtering or even with linear electro-optic modulators for picosecond pulses.
A frequency counter is an electronic instrument, or component of one, that is used for measuring frequency. Frequency counters usually measure the number of cycles of oscillation or pulses per second in a periodic electronic signal. Such an instrument is sometimes called a cymometer, particularly one of Chinese manufacture. [citation needed]
The transponder receives coded or single pulse interrogation from ground stations and transmits a single-pulse reply in the same frequency band. A common antenna is used for receiving and transmitting. The transponder consists of five functional systems: superheterodyne receiver, decoder, modulator, transmitter, and power supply.