Document Type and Number:
Japanese Patent JPS5717583
Kind Code:
Y2
Abstract:
1482971 Data transmission SIEMENS AG 24 July 1974 [6 Aug 1973] 32606/74 Addition to 1473941 Heading H4P In the digital transmission system of parent Specification in which digital signals are transmitted after frequency shifting by a frequency equal to half the bit repetition frequency the frequency shift is achieved by modulation by a carrier of half the bit repetition frequency whose zero transitions are displaced 90 degrees from the zero transitions of the digital signal, in a modulator whose output is zero for zero level carrier and/or signal, positive when carrier and signal are both positive or both negative, and negative when the carrier and signal are of opposite polarity. Preferably the modulation is carried out using an assembly of four NAND gates 27, 28, 29, 30, and two AND gates 31, 32 with the AND gate outputs fed to respective ends of the primary of a transformer 13 from whose secondary the frequency shifted output is derived.
Application Number:
JP14720680U
Publication Date:
April 13, 1982
Filing Date:
October 17, 1980
Export Citation:
International Classes:
H03M5/16; H04J1/04; H04J4/00; H04L27/04; H04L25/49; H04L27/02; H04L27/06; (IPC1-7): H04L27/04; H04L25/49