Transmission input/output device with reduced power consumption
First Claim
1. A transmission input/output device for outputting and inputting transmission signals transmitted through a telephone line, comprising:
- resistor means, connected to the telephone line, for setting a signal input and output impedance; and
transmission control circuit means for amplifying the transmission signals to be outputted to the telephone line, including;
variable resistor means, connected in series with the resistor means, for supplying voltages corresponding to the transmission signals to be outputted to the telephone line into the resistor means, said voltages varying as an impedance of the variable resistor means changes;
operational amplifier means, connected to the variable resistor means, for controlling the changes of the impedance of the variable resistor means according to the transmission signals; and
a negative feed back loop for providing a negative feed back of the voltages supplied from the variable resistor means to the operational amplifier means.
1 Assignment
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Accused Products
Abstract
A transmission input/output device for signal transmission through a telephone line, with reduced power consumption, size, and cost. The device includes: a resistor, connected to the telephone line, for setting a signal input and output impedance; and a transmission control circuit for amplifying the transmission signals to be outputted to the telephone line, including: a variable resistor, connected in series with the resistor, for supplying voltages corresponding to the transmission signals to be outputted to the telephone line into the resistor according to changes of an impedance of the variable resistor; and an operational amplifier for controlling the changes of the impedance of the variable resistor by supplying an output according to the transmission signals to be outputted to the variable resistor.
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Citations
7 Claims
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1. A transmission input/output device for outputting and inputting transmission signals transmitted through a telephone line, comprising:
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resistor means, connected to the telephone line, for setting a signal input and output impedance; and transmission control circuit means for amplifying the transmission signals to be outputted to the telephone line, including; variable resistor means, connected in series with the resistor means, for supplying voltages corresponding to the transmission signals to be outputted to the telephone line into the resistor means, said voltages varying as an impedance of the variable resistor means changes; operational amplifier means, connected to the variable resistor means, for controlling the changes of the impedance of the variable resistor means according to the transmission signals; and a negative feed back loop for providing a negative feed back of the voltages supplied from the variable resistor means to the operational amplifier means. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification