Spectrum Filters

Root Raised Cosine Model

This filter model has a response that is the square root of the Raised Cosine Filter response. When two Root Raised Cosine filters are placed in tandem on a link, the resulting response is the raised cosine response.

Parameter	Description
Upper Bandwidth Limit	The filter’s upper limit on the power spectrum. The bandwidth limit is relative to the carrier frequency (the carrier being at zero Hz), and is specified as a positive value. The upper limit is considered to be a sharp cutoff point and the spectrum is zero beyond the limit.
Lower Bandwidth Limit	The filter’s lower limit on the power spectrum. The bandwidth limit is relative to the carrier frequency and is specified as a negative value. The lower limit is considered to be a sharp cutoff point and the spectrum is zero beyond the limit.
Bandwidth	A read-only field equal to the difference between Upper Bandwidth Limit and Lower Bandwidth Limit. It is the total spectral bandwidth over which the filter has a defined response. The filter will only compute over frequencies that are in its defined response; outside its defined response, complete attenuation occurs.
Insertion Loss	A fixed signal attenuation with the spectrum loss computed by the filter’s response characteristics.
Roll-off Factor	A measure of excess bandwidth of the filter and smoothness of the filter characteristic response. Roll-off factor of zero (0 %) makes it a rectangular filter, while a factor of 1 (100 %) makes it a cosine filter.
Symbol Rate	The inverse of the symbol period of the data stream.

See Proakis, J., Digital Communications, 3rd ed., McGraw-Hill Inc. (1995).