Abstract:
A call is connected between secure terminals (16) through a network (12). If a network address for the call is included on an approved list (46), a secure call setup procedure (54) is performed automatically. One terminal (16) automatically sends an auto-secure signal. If the other terminal detects the auto-secure signal, secure call setup procedure (54) is performed automatically. The secure call setup procedure (54) determines a current user-identity for the opposing party. If the current user-identity corresponds to a user-identity included on an approved list (76), an abbreviated secure call setup process (80) is performed. If the current user identity is not approved, a full secure call setup process (78) is performed. The abbreviated process (80) differs from the full process (78) in that it uses a traffic key obtained from a prior secure communication session and may be performed more quickly.
Abstract:
An apparatus comprises a first and a second input and a processor coupled to the inputs. The processor estimates peak and minimum levels of each of the first and second input signals. A first signal regulator is coupled to the first input and to a first output for delivering a first output signal from the first signals. A second signal regulator is coupled to the second input and to a second output for delivering a second output signal from the second audio signals. A gain adjustment device is coupled to the processor and the first and second signal regulators. The gain adjustment device provides control signals to the first and second signal regulators to adjust an output signal level of the first output signal in response to minimum and peak levels of the first and second input signals. The output signal level is continuously variable over a range.
Abstract:
Methods and receiver circuits are provided for correlating an incoming signal with PN codes. An embodiment of the method includes receiving I/Q baseband samples in the I/Q domain; converting the I/Q baseband samples to phase baseband samples; generating a pseudonoise (PN) code; converting the PN code to PN phase data; performing a correlation on the phase baseband samples using the PN phase data to generate correlated I/Q values; performing an adding operation on the correlated I/Q values to generate demodulated I/Q values; converting the demodulated I/Q values into demodulated phase values; performing a frequency correction operation on the demodulated phase values to generate frequency correction data; converting the demodulated I/Q values into demodulated magnitude values; and performing signal decoding and synchronization on the magnitude values to generate output data. The operation of performing correlation on the phase baseband samples using the PN phase data is accomplished using scalar subtraction.
Abstract:
A method (50) reconstructs messages from segments (30) which are received in an unknown order and at different times. Each segment (30) comprises a header (31) and payload information (38). The method (50) reconstructs messages from the received segments (30) by reassembling the order as specified in the header (31) of the segment (30). Once the message is reconstructed, the message is delivered. This method (50) is especially important in satellite-based communications where no guarantee exists that the messages will be received in a sequential order or at a specified time.
Abstract:
A call is connected between secure terminals (16) through a network (12). If a network address for the call is included on an approved list (46), a secure call setup procedure (54) is performed automatically. One terminal (16) automatically sends an auto-secure signal. If the other terminal detects the auto-secure signal, secure call setup procedure (54) is performed automatically. The secure call setup procedure (54) determines a current user-identity for the opposing party. If the current user-identity corresponds to a user-identity included on an approved list (76), an abbreviated secure call setup process (80) is performed. If the current user identity is not approved, a full secure call setup process (78) is performed. The abbreviated process (80) differs from the full process (78) in that it uses a traffic key obtained from a prior secure communication session and may be performed more quickly.
Abstract:
A call is connected between secure terminals (16) through a network (12). If a network address for the call is included on an approved list (46), a secure call setup procedure (54) is performed automatically. One terminal (16) automatically sends an auto-secure signal. If the other terminal detects the auto-secure signal, secure call setup procedure (54) is performed automatically. The secure call setup procedure (54) determines a current user-identity for the opposing party. If the current user-identity corresponds to a user-identity included on an approved list (76), an abbreviated secure call setup process (80) is performed. If the current user identity is not approved, a full secure call setup process (78) is performed. The abbreviated process (80) differs from the full process (78) in that it uses a traffic key obtained from a prior secure communication session and may be performed more quickly.
Abstract:
A space-based communications network (10) includes satellites (12) placed in low-earth orbits (14). Satellites (12) engage in bulk communications with central switching offices (CSOs 22) and round control stations (GCSs 24). CSOs (22) and GCSs (24) include a network gateway (30) and any number-of remotely located earth terminals (32). Network gateway may provide telemetry, tracking and control functions for the constellation of satellites. Data are conveyed between the gateway (30) and earth terminals (32) over fiber optic cables (42) which convey a variety of different signals. Opposing unidirectional primary and secondary data communication channels each include signal sets having a gapped clock signal (76) and a data signal (86). The gapped clock signal (76) oscillates in synchronism with the data signal (86) and conveys both data timing and frame timing cable bundles (42) additionally convey LAN signals.