FSK MODULATOR

• Main Author: KIGUCHI MASAO
• Format: Patent
• Language: English
• Published: 08.01.1986
• Edition: 4
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

PURPOSE:To record precisely a picture changing from white to black on the receiving side by forming a control means for forcedly changing carrier frequency to black carrier frequency at the change of received serial data from the white level to the black level in an FSK modulator to be applied to a fascimile device. CONSTITUTION:Serial data SD and a carrier wave signal SC outputted from a frequency divider 2 are applied to a control circuit 5. The control circuit 5 generates a control pulse SS formed by adding a pulse to the carrier wave signal SC at the rise of the serial data SD from the white level to the black level and applies the control pulse SS to the load input terminal LD of the frequency devider 2. Therefore, the output, i.e. black frequency divided data DB, of a multiplexer 1 is set up in the frequency divider 2 at the timing of a control pulse SS corresponding to a pulse PP, so that a square wave signal SP is turned to frequency corresponding to the black carrier frequency at the change of the serial data SD from the white level to the black level and a sine wave signal ST is turned to the black carrier frequency.