Abstract A count-down circuit using a tunnel diode for counting down a repetition frequency of an input pulse signal applied from an input terminal to one electrode of the tunnel diode so as to produce a counted-down output from an output terminal connected to said one electrode of the tunnel diode, in which a seriesconnection comprising a resistor and a collector-emitter path of a transistor is connected to the output terminal. A bias current is applied through at least a part of the series-connection and the tunnel diode so that an operating point of the tunnel diode is maintained in a low-voltage region. A pulse generator is connected to a path between the input terminal and the tunnel diode for generating a pulse having a repetition period equal to an integer multiple of a repetition period of the input pulse signal in synchronism with the input pulse signal. A bistable circuit is connected to the base of the transistor so as to be set in response to each output pulse of the pulse generator and reset until a just succeeding one of output pulses of the pulse generator.
A count-down circuit, comprising: a tunnel diode; input terminal means for applying an input pulse signal to one electrode of an anode and a cathode of the tunnel diode; means defining an electrical path from of input terminal means to said tunnel diode; output terminal means connected to said one electrode of the tunnel diode for deriving therefrom an output pulse signal whose repetition frequency corresponds to a counteddown frequency of the repetition frequency of said input pulse signal; a series-connection connected to said output terminal means and comprising a resistor and a collector-emitter path of a transistor; bias means for passing a necessary bias current through said collector-emitter path, said resistor and said tunnel diode so that an operating point of said tunnel diode is maintained in a low-voltage region; a pulse generator connected to said input terminal means in a branch connection from said electrical path between said input terminal to said tunnel diode for generating a pulse having a repetition period equal to an integer multiple of a repetition period of the input pulse signal in synchronism with each one of the leading edges and the trailing edges of the input pulse signal; and a bistable circuit connected between the output of said pulse generator and the base of said transistor, the bistable circuit being set in response to each output pulse of said pulse generator and reset until a just succeeding one of output pulses of said pulse generator.
Claim 2
Dependent Claim
243 words
A count-down circuit, comprising: a tunnel diode; input terminal means for applying an input pulse signal to one electrode of an anode and a cathode of the tunnel diode; means defining an electrical path from of input terminal means to said tunnel diode; output terminal means connected to said one electrode of the tunnel diode for deriving therefrom an output pulse signal whose repetition frequency corresponds to a counteddown frequency of the repetition frequency of said input pulse signal; a series-connection connected to said output terminal means and comprising a resistor and a collector-emitter path of a transistor; bias means for passing a necessary bias current through said collector-emitter path, said resistor and said tunnel diode so that an operating point of said tunnel diode is maintained in a low-voltage region; a pulse generator connected to said input terminal means in a branch connection from said electrical path between said input terminal to said tunnel diode for generating a pulse having a repetition period equal to an integer multiple of a repetition period of the input pulse signal in synchronism with each one of the leading edges and the trailing edges of the input pulse signal; and a bistable circuit connected between the output of said pulse generator and the base of said transistor, the bistable circuit being set in response to each output pulse of said pulse generator and reset until a just succeeding one of output pulses of said pulse generator.
Claim 3
Dependent Claim
46 words
A count-down circuit according to claim 1, in which said bistable circuit comprises a reset input and including means connecting said output terminal means to the reset input of said bistable circuit to reset the bistable circuit in response to each one of said output pulses.
Claim 4
Dependent Claim
16 words
A count-down circuit according to claim 1, in which said pulse generator is a monostable multivibrator.