An apparatus and method provides synchronous communication in a communication environment (102) wherein multiple base stations are adapted to operate on the same frequencies. In particular, the base stations which operate within range of one another must be coordinated to minimize interference with other base stations which may otherwise operate independently. Each base station operating in a system will determine whether another base station operating on the same frequencies is within range (310). One of the base stations will assume a role as a master and the remaining base station will then synchronize to the master base station (312). The preferred methods for synchronizing the base stations includes signaling protocols (702, 902) and collision avoidance techniques for digital multiple access communication systems.

Method and Apparatus for Providing a Synchronous Communication Environment

A frequency modulated radio frequency broadcast network in which re-transmitting stations employ a synchronous frequency modulated booster system. Included in the frequency modulated booster system is a synchronous frequency modualted exciter for converting a frequency modulated intermediate frequency into a frequency modulated broadcast signal. The synchronous frequency modulated exicter includes phase locked loop circuits for synchronizing the re-transmitted frequency modulated broadcast signal with the frequency modulated intermediate frequency signal by detecting reference signals in the composite baseband of the intermediate frequency signal and in the composite signal frequency modulated broadcast signal.

Frequency modulated radio frequency broadcast network employing a synchronous frequency modulated booster system

A method and apparatus for synchronizing unrelated reference signals originating from two or more sources at different locations, which signals may be in different signal formats and/or subject to different delays at the receiving station. A master generator having an absolute time input from a highly stable time source generates a master reference signal having a frequency that is a common multiple of the frequencies of the unrelated reference signals. A counter is implemented from an arbitrary initial time point and the time elapsed from the initial time point to a synchronizing event is periodically encoded into the master reference signal as time code data. A slave generator associated with each information signal is genlocked to the master reference signal, and the time code data is encoded into the slave reference outputs. Each synchronizing event is thus associated with time code data specifying the absolute time of the synchronizing event, which can be inserted into an upstream position in the slave reference output associated with the information signal. Thus, two signals originating from different locations can be precisely synchronized so that transmission from one source to the other is synchronous and signal timings are known in advance.

Method and apparatus for synchronization of periodic signals

An imaging apparatus includes a camera device, a signal processor that receives a video signal from the camera, and a connection cable connecting the camera device and the signal processor. The camera device includes a first phase controller that compares the phase of a synchronization signal transmitted from the signal processor with the phase of an internal signal generated by the camera device, and that synchronizes the phase of the internal signal with the phase of the synchronization signal, a video synchronization signal generator that generates a video synchronization signal for the video signal based on the internal signal, and a signal transmitter that transmits the video signal. The signal processor includes a second phase controller that compares the phase of the video synchronization signal with the phase of the synchronization signal, and that synchronizes the phase of the video synchronization signal with the phase of the synchronization signal.

Imaging apparatus, phase control method, and synchronization method

Disclosed is a video camera apparatus including a video camera for generating a video signal and a camera control unit for generating a control signal for controlling the video camera. The camera control unit includes a video signal receiver, a video/reference signal phase comparator, a phase difference signal transmitter, a video signal memory, and write and read clock signal generators. The video camera comprises a phase difference signal receiver, a synchronizing signal generator, a synchronizing signal phase controller, an image pickup device and a video signal transmitter. In this setup, the output video signal is generated under stable genlock control for radio communication between video camera and camera control unit.

Video camera apparatus

The base station comprises a reference carrier generator and a synchronized carrier generator is provided in at least one remote station. Carrier synchronizing information is transmitted from the base station to the remote station and the synchronized carrier and information to be transmitted therewith are transmitted from the remote station to the base station. The base station has a periodically variable phase shifter to an input of which the synchronized carrier is applied, an output being coupled to a phase comparator to which in addition the reference carrier wave is applied. During first periods the phase shifter is subjected to a continuous phase shift. Second periods present in the first period are counted by a counter which is resettable under the control of the first periods. The counter is stopped by the phase comparator when a reference phase is reached during the phase shift. The counting result is numerical carrier synchronizing information, as required for a micro-processor or a micro-computer. The phase shift is effected incrementally, to an increasingly smaller portion of the carrier wave period near the zero phase.

Breimer Hendrik

Papers

Carrier synchronizing system for locking a remotely located carrier generator to a reference carrier generator at a base station