Understanding bandwidth Theories

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Bandwidth has an array of meanings, based on the context. Often the expression is related to a situation where a single frequency is superimposed on, combined with, or modulates a frequency that is different. A simple and fundamental example is its close relatives and amplitude modulation, frequency and phase modulation.

AMWhen speaking of the frequency of a broadcast station, it’s The carrier. The situation is more complicated because, in amplitude modulation, the carrier is modulated by a sound frequency. Its amplitude oscillates, in any moment relating to the amplitude, although the carrier’s frequency is unchanged. The carrier is said to possess an envelope, which can be displayed on the screen of an oscilloscope.

When an audio signal is superimposed on an RF carrier, Sidebands in difference and the sum of the carrier frequency are generated. The transmitted signal is therefore dispersed in frequency. The broadcaster decides the bandwidth of the signal by choosing the high-frequency cutoff of the sound as transmitted.

Frequency modulation spectra

An FMed carrier’s spectrum consists of the carrier An infinite number of sidebands spreading out on either side of the carrier at multiples of the frequency. The heights of the sidebands is set by the index the frequencyf the carrier varies around its unmodulated level. As an FMed signal has sidebands that extend out to infinity, it’s normal practice to talk of their bandwidth as that which comprises approximately 98% of the signal power.

what is bandwidth

The AM band is more compact compared to the band. Regulatory agency, the FCC, allocates a bandwidth for each broadcaster so their signals will not interfere. It is the broadcaster’s responsibility to refrain from regulating the carrier with high-frequency tones which could extend the bandwidth beyond statutory limits. Greater bandwidth is allowed for FM broadcasters because signals, that don’t bounce off the ionosphere but propogate just on the basis of sight, cover a smaller area. For this reason, most music programming, which requires sound, is broadcast via FM. AM is utilized more for talk radio, where high-frequency response is not as critical.

Single sideband, as a transmission method, gets the Benefit of utilizing transmitter power and bandwidth in a more effective method. Conventional AM is made up of the carrier and two sidebands (additive and difference signals) all which carry the identical info. By suppressing one of the sidebands, which may be done using filters, this duplication can be prevented. Therefore, bandwidth and power requirements are reduced in one stroke. The drawback is greater complexity at the receiver in tuning and demodulation.

Scope bandwidthIn regard to systems or Communications stations has a meaning. It is a measure. A 1-GHz oscilloscope, as an example, can display signals that do not exceed 1 GHz. But that is not the whole story. Until it’s lost beneath the noise floor of the tool as the bandwidth limit is approached, the signal is attenuated. In establishing the bandwidth of the tool, an exact attenuation level has to be specified.

what is bandwidth

The dB level is your oscilloscope’s summit response. Bandwidth of the oscilloscope is the maximum frequency that could get through the front end with less than 70 percent attenuation, which is -3 dB of the signal at the oscilloscope input. This is for an perfect sine wave. Square waves and similar signs with rising and falling edges cannot be hauled in the bandwidth of the instrument.


Another meaning of bandwidth would be the speed of Data transfer to another. Contribute to this metric. To quantify bandwidth in this sense, rather than Frequency in Hertz, bits (or kbits, Mbits, Gbits) each second are used.