Noise suppression circuit

Claim 2

A noise suppression circuit comprising: a transistor, the collector thereof being connected to a power supply; a diode and an impedance means capable of passing direct current connected in series between the emitter and the collector of said transistor; a constant current circuit connected between the emitter of said transistor and ground for maintaining constant the sum of the emitter current of said transistor and the current flowing through said diode; a DC restorer connected between the coNnecting point of said impedance means and said diode and ground; means for supplying an input signal to the base of said transistor; and means for generating an output signal across said impedance means.

Claim 3

A noise suppression circuit as claimed in claim 1, wherein said impedance means comprises a resistor.

Claim 4

A noise suppression circuit as claimed in claim 1, wherein said impedance means comprises a resistor, and said DC restorer comprises a second diode, a second constant current circuit connected in series with said second diode, and a capacitor connected in parallel with said second constant current circuit.

Claim 5

A noise suppression circuit comprising: a transistor, the collector thereof being connected to a power supply; a first diode and a resistor connected in series between the emitter of said transistor and said power supply; a first constant current circuit connected between the emitter of said transistor and ground for maintaining constant the sum of the emitter current of said transistor and the current flowing through said first diode; a second diode and a second constant current circuit connected in series between the connecting point of said resistor and said first diode and ground; a capacitor connected in parallel with said second constant current circuit for being charged with current flowing through said second diode and discharging through said second constant current circuit; means for supplying an input signal to the base of said transistor; and means for generating an output signal in which noise is suppressed across said resistor.

Claim 6

A noise suppression circuit comprising: a transistor, the collector thereof being connected to a power supply; a first diode and a resistor connected in series between the emitter of said transistor and said power supply; a first constant current circuit connected between the emitter of said transistor and ground for maintaining constant the sum of the emitter current of said transistor and the current flowing through said first diode; a second diode and a second constant current circuit connected in series between the connecting point of said resistor and said first diode and ground; a capacitor connected in parallel with said second constant current circuit for being charged with current flowing through said second diode and discharging through said second constant current circuit; means for supplying an input signal to the base of said transistor; and means for generating an output signal in which noise is suppressed across said resistor.

Claim 7

A noise suppression circuit as claimed in claim 4, wherein said first and second constant current circuits comprise a second transistor and a third transistor respectively which are connected at the bases thereof to said power supply to be supplied with a constant base bias voltage.

Claim 8

A noise suppression circuit comprising: a first transistor, the collector thereof being connected to a power supply; a first diode and a resistor connected in series between the emitter of said first transistor and said power supply; a first constant current circuit connected between the emitter of said first transistor and ground for maintaining constant the sum of the emitter current of said first transistor and the current flowing through said first diode; a second diode and a second constant current circuit connected in series between the connecting point of said resistor and said first diode and ground; a capacitor connected in parallel with said second constant current circuit for being charged with current flowing through said second diode and discharging through said second constant current circuit; means for supplying an input signal to the base of said first transistor; a pair of a second and a third transistor, the emitters of said second and third transistors of said pair being connected through a third constant current circuit to ground, the base of said second transistor of said pair being connected to the emitter of said first transistor to be supplied with said input signal, the base of said third transistor of said pair being connected to the connecting point of said second diode and said capacitor to be supplied with a DC voltage whose value is proportional to the peak value of said input signal, and one of the collectors of said second and third transistors of said pair being connected to the connecting point of said resistor and said first-mentioned diode so that an inverted pulse appears at said collector when a noise whose amplitude is greater than a predetermined value is contained in said input signal; and means for generating an output signal in which the noise is suppressed or cancelled at the connecting point of said resistor and said first diode.

Claim 9

A noise suppression circuit comprising: a first transistor, the collector thereof being connected to a power supply; a first diode and a resistor connected in series between the emitter of said first transistor and said power supply; a first constant current circuit connected between the emitter of said first transistor and ground for maintaining constant the sum of the emitter current of said first transistor and the current flowing through said first diode; a second diode and a second constant current circuit connected in series between the connecting point of said resistor and said first diode and ground; a capacitor connected in parallel with said second constant current circuit for being charged with current flowing through said second diode and discharging through said second constant current circuit; means for supplying an input signal to the base of said first transistor; a pair of a second and a third transistor, the emitters of said second and third transistors of said pair being connected through a third constant current circuit to ground, the base of said second transistor of said pair being connected to the emitter of said first transistor to be supplied with said input signal, the base of said third transistor of said pair being connected to the connecting point of said second diode and said capacitor to be supplied with a DC voltage whose value is proportional to the peak value of said input signal, and one of the collectors of said second and third transistors of said pair being connected to the connecting point of said resistor and said first-mentioned diode so that an inverted pulse appears at said collector when a noise whose amplitude is greater than a predetermined value is contained in said input signal; and means for generating an output signal in which the noise is suppressed or cancelled at the connecting point of said resistor and said first diode.

Claim 10

A noise suppression circuit comprising: a first transistor, the collector thereof being connected to a power supply; a first diode and a first resistor Connected in series between the emitter of said first transistor and said power supply; a first constant current circuit connected between the emitter of said first transistor and ground for maintaining constant the sum of the emitter current of said first transistor and the current flowing through said first diode; a second diode and a second constant current circuit connected in series between the connecting point of said first resistor and said first diode and ground; a capacitor connected in parallel with said second constant current circuit for being charged with current flowing through said second diode and discharging through said second constant current circuit; means for supplying an input signal to the base of said first transistor; a pair of second and a third transistor, the emitters of said second and third transistors of said pair being connected through a third constant current circuit to ground, the base of said second transistor of said pair being connected to the emitter of said first transistor to be supplied with said input signal, the base of said third transistor of said pair being connected to the connecting point of said second diode and said capacitor to be supplied with a DC voltage whose value is proportional to the peak value of said input signal, and one of the collectors of said second and third transistors of said pair being connected to the connecting point of said first resistor and said first diode so that an noise cancelling pulse thereto inverted pulse appears at said collector when noise whose amplitude is greater than predetermined value is contained in said input signal; a second resistor and a third diode connected in series between the emitter and the collector of said first transistor; a fourth diode and a third resistor connected in series between the connecting point of said second resistor and said third diode and the connecting point of said second diode and said second constant current circuit for supplying a charging current through said second resistor and said fourth diode to said capacitor when noise whose amplitude is greater than a predetermined value is contained in said input signal; and means for generating an output signal in which the noise is suppressed or cancelled at the connecting point of said first resistor and said first diode.

Claim 11

A noise suppression circuit comprising: a first transistor, the collector thereof being connected to a power supply; a first diode and a first resistor Connected in series between the emitter of said first transistor and said power supply; a first constant current circuit connected between the emitter of said first transistor and ground for maintaining constant the sum of the emitter current of said first transistor and the current flowing through said first diode; a second diode and a second constant current circuit connected in series between the connecting point of said first resistor and said first diode and ground; a capacitor connected in parallel with said second constant current circuit for being charged with current flowing through said second diode and discharging through said second constant current circuit; means for supplying an input signal to the base of said first transistor; a pair of second and a third transistor, the emitters of said second and third transistors of said pair being connected through a third constant current circuit to ground, the base of said second transistor of said pair being connected to the emitter of said first transistor to be supplied with said input signal, the base of said third transistor of said pair being connected to the connecting point of said second diode and said capacitor to be supplied with a DC voltage whose value is proportional to the peak value of said input signal, and one of the collectors of said second and third transistors of said pair being connected to the connecting point of said first resistor and said first diode so that an noise cancelling pulse thereto inverted pulse appears at said collector when noise whose amplitude is greater than predetermined value is contained in said input signal; a second resistor and a third diode connected in series between the emitter and the collector of said first transistor; a fourth diode and a third resistor connected in series between the connecting point of said second resistor and said third diode and the connecting point of said second diode and said second constant current circuit for supplying a charging current through said second resistor and said fourth diode to said capacitor when noise whose amplitude is greater than a predetermined value is contained in said input signal; and means for generating an output signal in which the noise is suppressed or cancelled at the connecting point of said first resistor and said first diode.

Claim 12

A noise suppression circuit as claimed in claim 7, wherein each of said first, second and third constant current circuits comprises a transistor whose base is connected to said power supply for supplying constant current therethrough.