# Accession Number:

## AD0649621

# Title:

## SIGNAL TO NOISE RATIOS FOR MULTIPATH COMBINES. PART II. THE INITIAL TRANSIENT PERIOD OF OPERATION.

# Descriptive Note:

## Engineering rept.,

# Corporate Author:

## RAYTHEON CO WALTHAM MASS RESEARCH DIV

# Personal Author(s):

# Report Date:

## 1962-10-04

# Pagination or Media Count:

## 19.0

# Abstract:

The transient period of combiner operation has the same form of combiner performance factor viz. the signal to noise ratio divided by the signal to noise ratio plus the effective noise level input quantities as the steady state period except that the effective noise level is different. In the initial period of combiner operation starting from an empty storage condition the effective noise level is approximately the sum of the two channel noises times the reciprocal of the number of bauds integrated over. In the initial period of combiner operation starting with the steady state amount of noise, the effective noise level is approximately the sum of the two channel noises times one-half the effective number of bauds integrated over in the steady state times the inverse square of the number of bauds actually integrated over during the transient period. If only one signal is sent during the initial period, the effective signal to noise ratio for the learning period is increased by 3 db. During the initial learning period, the energy expended by the transmitter can be best utilized if the power increases from baud to baud as the inverse square of the loop gain. During the learning period, the loop gain should be as close to unity as is feasible. The minimum interference to other users will occur if the learning period is as long as is possible. Author

# Descriptors:

# Subject Categories:

- Radio Communications