Abstract: An interference canceling system in which a phase lock loop is utilized as narrow band tracking filter to adaptively lock to interference tones to be canceled by a process of signal subtraction.

Abstract: A code generator produces one sequence of coded pulses having a predetermined code pattern. This sequence of coded pulses is transmitted to a remote point and received from the remote point to provide a replica of the sequence of coded pulses. A correlator is coupled to the generator and receiver responsive to the sequence and its replica to produce due to the predetermined code pattern an impulse output only when the sequence and its replica are time coincident and a zero output at all other time relationships between the sequence and its replica.

Abstract: A class of pseudo-noise multiplexed codes including coding mates having cooperating autocorrelation function which upon detection provides an impulse autocorrelation function. The code mates include at least one blank digit slot in the repetitious period of at least one of the codes of the code mates. One form requires a digit of either binary condition in the first and last digit slot of the code structure with the blank slot being disposed therebetween. The number of code mates can be increased by repeatedly solving the equations of FIG. 5 for the original code mates and the resultant new code mates. The interleaving process required in the equations is achieved by logic circuitry controlled by a control signal having a period equal to the period of a digit slot of the input code mates.