Resources Contact Us Home
Polarization direction synchronization detecting circuit and receiving apparatus

Image Number 7 for United States Patent #8131160.

A switch is to be inputted a modulation signal including the synchronization signal extracted from a received communication signal as a control signal, is to be inputted a detection signal detected by a photodetector that receives a polarization modulation signal adjusted to a polarization direction of a quantum cipher signal, and selectively switches and outputs one of the detection signal and an inverted signal of the detection signal according to the control signal. A low-pass filter outputs the output signal of the switch, whereby a plus level signal is outputted when a relative angle difference .DELTA..theta. between polarization axes on a transmission side and a reception side is larger than a predetermined polarization angle, a 0 level signal is outputted when .DELTA..theta. is equal to the predetermined polarization angle, and a minus level signal is outputted when .DELTA..theta. is in a range of the predetermined polarization angle from 0 degree.

  Recently Added Patents
Biomedical electro-stimulator
Clostridium chauvoei polypeptide, DNA encoding the polypeptide and a vaccine comprising the polypeptide
Detecting the type of NAT firewall using messages
Apparatus and method for multiplying frequency of a clock signal
Inspection systems and methods for detecting defects on extreme ultraviolet mask blanks
Flame-proofed thermoplastic compositions
Reovirus for the treatment of cellular proliferative disorders
  Randomly Featured Patents
Hat mounted music system
Detector for sensing the angular position of a rotatable magnet
Method and apparatus for interleaving display buffers
Pipe supports
Particulate sauce dispensing nozzle
Motorcycle triple tree
Computer-aided manufacturing support method and system for specifying relationships and dependencies between process type components
System and methods for forming bushing plates
Eyeglasses clip
Image forming apparatus