Frequency keying device for binary data transmission - receives signals from two generators, applied through AND=gates to flip=flop, to which binary signal are also applied

摘要

Each of the two frequencies (f1, f2) represents a binary state. Two pulse generators (1, 2) generate pulse trains with frequencies 2n.f1 and 2n.f2 applied to two first AND gates (4, 5), and both together to a third AND gate (6). Negated output of the latter is applied to the clock input (7a) of a flip-flop (7), and the binary signals to be transmitted are applied to this flip-flop preparation input (7b). Flip-flop outputs are connected to one input each of the two AND gates (4, 5), and their negated outputs to a fourth AND gate (8) whose negated output is connected to a frequency divider (9) with division ratio of 2n.