| 摘要 |
PURPOSE:To improve the transmission speed and sensitivity by providing a waveform shaping device before a band pass filter to suppress the fluctuation of pulse width after waveform shaping even with a different input signal level thereby increasing the noise margin of a data transmitter. CONSTITUTION:A carrier fAF modulating a high frequency carrier with a binary data pulse from an antenna is received by a front end 2, amplified (3) and a large or a small signal A is inputted to a low frequency wafeform shaping device 8. The shaping device 8 shapes interms of waveform the signal A into a signal B of the same amplitude by using a threshold voltage VS1, the low frequency component is passed by a BPF4 and a signal D is outputted from a diode 5. The signal D is integrated by an integration device 6, a signal E is fed to a waveform shaping device 7 to apply waveform shaping by using a threshold voltage VS2 thereby outputting a signal F with a required pulse width. If the input signal level is different, the shaping device 8 suppresses the fluctuation of the pluse width, the noise margin of the transmitter is improved thereby improving the transmission performance. |
