1.   She faces what is known as a signal extraction problem.

2.   This is the signal extraction problem.

3.   Workers face the signal extraction problem of deciding whether the increase in real wages is transitory or lasting.

4.   Cable points out that DBS is not without signal problems -- interruptions caused by storms and digital artifacts that sometimes appear on the screen.

5.   The field could become Balkanized, creating both compatibility and signal interference problems for users.

6.   The Paddington crash and others like it were caused by signal problems.

7.   Thousands of Long Island Rail Road commuters bound for Penn Station were delayed during the morning rush hour by signal problems.

8.   Amtrak canceled trains running between New York and Florida for fear of flooding, fallen trees and signal problems.

9.   Trains running between New York and Florida were canceled because of the threat of flooding, fallen trees and signal problems, a spokesman for Amtrak said.