What is the exact expression for adjacent channel rejection ratio ?

what is the exact expression for adjacent channel rejection ratio ?

Is it also defined the allowable signal power in the adjacent channel?

Hello fanshuo,


Adjacent Channel Rejection Ratio (ACRR):

The performance of a filter is normally specified in terms of a Rejection Ratio.
This indicates the filter's relative gain (?loss?) at the center of the passband compared to just outside.
It is conventional to specify this in either of two ways:
the Adjacent Channel Rejection Ratio and the Alternate Channel Rejection Ratio.

The adjacent channels are those immediately on either side of the wanted
(tuned) channel.

Selectivity is usually measured as a ratio in decibels (dBs),
comparing the signal strength received against that of a similar signal on another frequency.
If the signal is at the adjacent channel of the selected signal,
this measurement is also known as adjacent-channel rejection ratio (ACRR).


Adjacent Channel Power Ratio (ACPR):

The adjacent channel power ratio is computed as the ratio of the power in
the adjacent channel to the power in the base channel:

ACPR = Pavg,adj/Pavg,ch

where Pavg,adj and Pavg,ch are the average channel power in the adjacent
and base channels, respectively.


for more information:
http://focus.ti.com/pdfs/bcg/80211_acr_wp.pdf



---manju---

In Receiver, it also means adjacent channel selectivity(ACS), which depends on LO's phase noise, linearity and channel filter..