System and method for synchronization tracking in an in-band modem
First Claim
Patent Images
1. A method for identifying a sample slip in the transmission channel of an in-band modem comprising:
- receiving a data bit, wherein the received data bit comprises a pulse positioned at one of a plurality of predetermined locations in a frame;
correlating the received data bit with a reference signal; and
identifying a sample slip based on the correlating,wherein the correlating comprises a two-stage search,wherein a first stage of the two-stage search comprises finding a plurality of possible maximum correlations within a first predetermined range around each of a first predetermined number of pulses in a frame, andwherein a second stage of the two-stage search comprises finding the maximum correlation among the possible maximum correlations.
1 Assignment
0 Petitions
Accused Products
Abstract
Processing the synchronization of an inband modem to detect sample slip conditions is disclosed. Decision logic reliably detects the sample slip condition while minimizing the number of false alarms.
-
Citations
19 Claims
-
1. A method for identifying a sample slip in the transmission channel of an in-band modem comprising:
-
receiving a data bit, wherein the received data bit comprises a pulse positioned at one of a plurality of predetermined locations in a frame; correlating the received data bit with a reference signal; and identifying a sample slip based on the correlating, wherein the correlating comprises a two-stage search, wherein a first stage of the two-stage search comprises finding a plurality of possible maximum correlations within a first predetermined range around each of a first predetermined number of pulses in a frame, and wherein a second stage of the two-stage search comprises finding the maximum correlation among the possible maximum correlations. - View Dependent Claims (2, 3, 4, 5)
-
-
6. An apparatus for identifying a sample slip in the transmission channel of an in-band modem comprising:
-
a receiver for receiving a data bit, wherein the received data bit comprises a pulse positioned at one of a plurality of predetermined locations in a frame; a correlator for correlating the received data bit with a reference signal and a processor for identifying a sample slip based on the correlating wherein the correlator comprises a two-stage searcher, wherein a first stage of the two-stage searcher comprises finding a plurality of possible maximum correlations within a first predetermined range around each of a first predetermined number of pulses in a frame, and wherein a second stage of the two-stage searcher comprises finding the maximum correlation among the possible maximum correlations. - View Dependent Claims (7, 8, 9, 10)
-
-
11. An apparatus for identifying a sample slip in the transmission channel of an in-band modem comprising:
-
means for receiving a data bit, wherein the received data bit comprises a pulse positioned at one of a plurality of predetermined locations in a frame; means for correlating the received data bit with a reference signal; and means for identifying a sample slip based on the correlating, wherein the means for correlating comprises a two-stage search, wherein a first stage of the two-stage search comprises means for finding a plurality of possible maximum correlations within a first predetermined range around each of a first predetermined number of pulses in a frame, and wherein a second stage of the two-stage search comprises means for finding the maximum correlation among the possible maximum correlations. - View Dependent Claims (12, 13, 14, 15)
-
-
16. A non-transitory memory storing a computer program that, when executed, causes a computer to perform the acts of:
-
receiving a data bit, wherein the received data bit comprises a pulse positioned at one of a plurality of predetermined locations in a frame; correlating the received data bit with a reference signal; and identifying a sample slip based on the correlating, wherein the correlating comprises a two-stage search, wherein a first stage of the two-stage search comprises finding a plurality of possible maximum correlations within a first predetermined range around each of a first predetermined number of pulses in a frame, and wherein a second stage of the two-stage search comprises finding the maximum correlation among the possible maximum correlations. - View Dependent Claims (17, 18, 19)
-
Specification