Abstract: A spread spectrum communication system is provided in which a receiver is adapted to despread multi-bit digital signals transmitted with a fixed chipping rate using two or more different spreading code lengths. As a result, a longer spreading code could be utilized to transmit at a lower data rate for conditions in which jamming resistance is more critical, such as over longer distances, and a shorter spreading code could be utilized to transmit at a higher data rate for conditions in which jamming resistance is less critical, such as over shorter distances. The receiver further comprises a digital matched filter adapted to correlate to the two different spreading codes. The digital matched filter comprises a digital delay line having a plurality of successive delay stages that propagate the received digital signal therethrough at a fixed rate corresponding to the chipping rate of the digital signal.

Abstract: A secure communication system is provided for transmitting a country specific frequency allocation in encrypted form between a host processor and a remote device. The secure communication system comprises a host processor and a remote device capable of communicating with the host processor over a communication link. The host processor has a plurality of stored data sets and a predefined encryption algorithm. Each one of the stored data sets comprises a country specific frequency allocation. The remote device has a unique identifier code and also has the predefined encryption algorithm. Responsive to the unique identifier code, the host processor provides a selected one of the plurality of data sets in encrypted form by utilizing the predefined encryption algorithm. The unique identifier code provides an encryption key for the predefined encryption algorithm. The remote device then decrypts the encrypted data set using the predefined encryption algorithm with the identifier code as a decryption key.

Abstract: A secure communication system is provided for transmitting a country specific frequency allocation in encrypted form between a host processor and a remote device. The secure communication system comprises a host processor and a remote device capable of communicating with the host processor over a communication link. The host processor has a plurality of stored data sets and a predefined encryption algorithm. Each one of the stored data sets comprises a country specific frequency allocation. The remote device has a unique identifier code and also has the predefined encryption algorithm. Responsive to the unique identifier code, the host processor provides a selected one of the plurality of data sets in encrypted form by utilizing the predefined encryption algorithm. The unique identifier code provides an encryption key for the predefined encryption algorithm. The remote device then decrypts the encrypted data set using the predefined encryption algorithm with the identifier code as a decryption key.