公开(公告)号：CA2139191A1

公开(公告)日：1995-06-30

申请号：CA2139191

申请日：1994-12-28

Applicant: KOREA ELECTRONICS TELECOMM ,  KOREA TELECOMMUNICATION

Inventor： CHANG DAE I ,  KIM JEONG H

IPC: H03L7/06 ,  H03D7/16 ,  H03L7/183 ,  H04B1/04 ,  H04B7/19 ,  H03L7/085 ,  H04B7/185

Abstract: The present invention relates to a transmit reference oscillator for a remote station of a VSAT for satellite communications. comprises a by-fifteen divider for dividing input reference signals by 15: a Voltage Controlled Oscillator (VCO) for outputting oscillation signals; a by-four divider for dividing the oscillating signals outputted from said voltage controlled oscillator: a by-N divider for dividing by N the signals divided by said by-N divider; a phase detector for outputting phase difference signals, which are the signals of the phase differences obtained by comparing the output signals of said by-N divider and those of said by-fifteen divider; and a low pass filter for varying the oscillation signals of said voltage controlled oscillator by filtering the difference signals outputted from said phase detector and applying the filtered difference signals to said voltage controlled oscillator. Accordingly, the present invention not only can transmit data over the whole band of 500 MHz which is a bandwidth for satellite communication transponders, without modifying a remote station or a Radio Frequency (RF) part of a VSAT, but also is proof against phase noises and spurious, and can be simply implemented to reduce its size and lower its price.