it states the power and energy of a given signal in terms of frequency

Bandwidth has several related meanings:

* Bandwidth (computing) or digital bandwidth: a rate of data transfer, throughput or bit rate, measured in bits per second

* Bandwidth (signal processing) or analog bandwidth, frequency bandwidth or radio bandwidth: a measure of the width of a range of frequencies, measured in hertz

* Spectral linewidth: the width of an atomic or molecular spectral line, measured in hertz

Bandwidth can also refer to:

* Bandwidth (linear algebra), the width of the band of nonzero terms around the diagonal of a matrix

* In kernel density estimation, "bandwidth" describes the width of the convolution kernel used

* A normative expected range of linguistic behavior in language expectancy theory

* In business jargon, the resources needed to complete a task or project

* Bandwidth (radio program): A Canadian radio program

In bandwidth is defined a frequency span - the difference between a high frequency and a lower frequency.

1.Find the Fourier Transform of the pulse used to transmit data over the channel.

2.Determine the bitrate of the signal by the modulation format (QPSK for example has 2bits/symbol so 1 symbol per second would equate to 2 bits/s)

3.The first null in the Fourier transform is the required bandwidth (~0.75 x bitrate in optical communications, depends on channel)

4. Divide bits/s by the required bandwidth to find the spectral efficiency.

Greater efficiency, and the ability to remove signal variations and noise are just a few of the advantages of RF modules. Disadvantages include the need for filters to limit bandwidth and lower spectral efficiency.

what is spectral evidence

Spectrum (spectral) refers to different frequencies of light associated with a substance.