公开(公告)号：US3660601A

公开(公告)日：1972-05-02

申请号：US3660601D

申请日：1970-06-10

申请人： IBM

发明人： DOBSON DONALD R

IPC分类号： H04L27/14 ,  H04L15/24

CPC分类号： H04L27/14

摘要： A system for detecting frequency shift keying information on a real time basis independent of the amplitude of the input FSK signal. The second derivative of the input voltage waveform signal which is in exact phase with the input signal is obtained. The gain of the differentiated voltage signal is controlled so that when the input signal has a frequency below predetermined frequency, the magnitude o2 the differentiated voltage signal will be less than the magnitude of the input voltage signal at all points except zero; and when the input signal exceeds the predetermined frequency, the magnitude of the differentiated voltage signal exceeds that of the input voltage signal. The input signal and the gain controlled differentiated signal are magnitude compared and an output signal representative of the result of the comparison and hence of the frequency of the input signal is supplied. A low pass filter introducing minimal signal delay is utilized to remove possible logic silvers at the time when both signals are zero and when there is an input frequency change.

摘要翻译： 独立于输入FSK信号的幅度的实时检测频移键控信息的系统。 获得与输入信号精确相位的输入电压波形信号的二次导数。 控制差分电压信号的增益，使得当输入信号的频率低于预定频率时，微分电压信号的幅度o2将小于零点以外的所有点的输入电压信号的幅度; 并且当输入信号超过预定频率时，微分电压信号的大小超过输入电压信号的幅度。 输入信号和增益受控的微分信号是比较的幅度，并且提供表示比较结果和因此输入信号的频率的输出信号。 引入最小信号延迟的低通滤波器用于在两个信号为零时以及当输入频率变化时消除可能的逻辑银。