Title:
【発明の名称】伝送線路長測定装置
Document Type and Number:
Japanese Patent JP2571082
Kind Code:
B2
Abstract:
PURPOSE:To execute the measurement with high accuracy and with high time resolution in a short time by allowing a timing comparison pulse signal to pass through only while phase difference information signals which are varied in accordance with the phase polarity between input signals to be measured to not coincide. CONSTITUTION:A phase difference detecting circuits S1, S2 output a high level as positive phase shift information, when the timing of a timing comparison pulse PR is delayed comparing with the other timing, and output phase difference information signals OUT+1, OUT+2 of NRZ for outputting a low level as a negative phase shift, respectively, in case of the contrary. As for these signals OUT+1, OUT+2, exclusive OR is taken by an EX-OR gate 4, and also, as for the pulse PR and an output signal EOR of the gate 4, AND is taken by an AND gate 5, and only when the output EOR of the gate 4 is high, the pulse PR is outputted from the gate 5. An output signal AND of the gate 5 is inputted to a clock terminal CK of a counter 6, and the number of pulses is counted.
Inventors:
OTSUJI TAIICHI
Application Number:
JP30932687A
Publication Date:
January 16, 1997
Filing Date:
December 07, 1987
Export Citation:
Assignee:
NIPPON TELEGRAPH & TELEPHONE
International Classes:
G01R31/11; H04B3/46; H04B3/462; G01R31/28; (IPC1-7): G01R31/28; G01R31/11; H04B3/46
Attorney, Agent or Firm:
Toshio Takayama (1 person outside)