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A sweep generator is a piece of electronic test equipment similar to, and sometimes included on, a function generator which creates an electrical waveform with a linearly varying frequency and a constant amplitude. Sweep generators are commonly used to test the frequency response of electronic filter circuits.
As with the component testing, another signal being injected into the output of a signal generator can cause intermodulation distortion within the generator. Isolators are included in the test set up as with the component testing. [10] The combined test signal can be injected directly in to the receiver if the antenna is removable.
An RF sweep relates to a receiver which changes its frequency of operation continuously from a minimum frequency to a maximum (or from maximum to minimum). Usually the sweep is performed at a fixed, controllable rate, for example 5 MHz/sec. Some systems use frequency hopping, switching from one frequency of operation to another.
A shaker is a device that excites the object or structure according to its amplified input signal. Several input signals are available for modal testing, but the sine sweep and random frequency vibration profiles are by far the most commonly used signals. Small objects or structures can be attached directly to the shaker table. With some types ...
Radiation pattern of an antenna can be defined as the locus of all points where the emitted power per unit surface is the same. The radiated power per unit surface is proportional to the squared electrical field of the electromagnetic wave. The radiation pattern is the locus of points with the same electrical field.
A completely different approach to function generation is to use software instructions to generate a waveform, with provision for output. For example, a general-purpose digital computer can be used to generate the waveform; if frequency range and amplitude are acceptable, the sound card fitted to most computers can be used to output the generated wave.
A wobbulator is an electronic device primarily used for the alignment of receiver or transmitter intermediate frequency strips. It is usually used in conjunction with an oscilloscope, to enable a visual representation of a receiver's passband to be seen, hence simplifying alignment; it was used to tune early consumer AM radios.
An initial SFRA test is carried out to obtain the signature of the transformer frequency response by injecting various discreet frequencies. This reference is then used for future comparisons. A change in winding position, degradation in the insulation, etc. will result in change in capacitance or inductance thereby affecting the measured ...