Senin, 24 Oktober 2011

Sweep-Frequency


Sweep-Frequency Generator The working of a sweep-frequency generator is explained in the article below. The working and block diagram of an electronically tuned sweep frequency generator and its different parameters are also explained. Related Article SIGNAL GENERATORS A sweep frequency generator is a type of signal generator that is used to generate a sinusoidal output. Such an output will have its frequency automatically varied or swept between two selected frequencies. One complete cycle of the frequency variation is called a sweep. depending on the design of a particular instrument, either linear or logarithmic variations can be introduced to the frequency rate. However, over the entire frequency range of the sweep, the amplitude of the signal output is designed to remain constant. Sweep-frequency generators are primarily used for measuring the responses of amplifiers, filters, and electrical components over various frequency bands. The frequency range of a sweep-frequency generator usually extends over three bands, 0.001 Hz – 100 kHz (low frequency to audio), 100 kHz – 1,500 MHz (RF range), and 1-200 GHz (microwave range). It is really a hectic task to know the performance of measurement of bandwidth over a wide frequency range with a manually tuned oscillator.

Signal Generators In this article, the detailed explanation of a signal generator is given. The principles of signal modulation, the block diagram of an AM signal generator and the measures needed to achieve a stable frequency output is explained below. RELATED ARTICLE SWEEP FREQUENCY GENERATOR Like an oscillator, a signal generator is also a source of sinusoidal signals. The main difference between a signal generator and an oscillator is that a signal generator is capable of modulating its sinusoidal output signal with other signals. When signal generators are used for producing an unmodulated sinusoidal output they are said to be producing continuous height wave [CW] signal. When the produced output signal is modulated, the modulating waveforms may be either externally applied sine-waves, square waves, triangular waves, pulses or more complex signals, as well as internally generated sine-waves. Amplitude modulation (AM) or frequency modulation (FM) may be used. Normally amplitude (AM) modulation is employed. Principles of amplitude modulation (AM) and frequency modulation (FM) are illustrated in the figure shown below. Signal Modulaton Signal Generator – Applications Signal generators are primarily employed for providing appropriate signals for calibration, testing and troubleshooting of the amplifier circuits used in communication.

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