Electronic inductor circuit using cascoded transistors
First Claim
1. An electronic inductor circuit comprising:
- an input node connected to a telephone line;
a ground node;
a first transistor device having a first terminal connected to the input node, a second terminal and a third terminal;
a second transistor device having a first terminal connected to the third terminal of the first transistor device, a second terminal and a third terminal;
a resistor connected between the third terminal of the second transistor device and the ground node;
a resistor biasing network connected between the input node and the ground node and to the second terminal of the first and second transistor devices for electrically biasing the transistor devices; and
a capacitor connected between the second terminal of the first transistor device and the ground node.
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Accused Products
Abstract
An electronic inductor circuit comprises a pair of cascoded Darlington bipolar or MOSFET transistors, configured such that the impedance presented by the collector (drain) of the top transistor of the electronic inductor is increased, relative to the other resistive components in the electronic inductor circuit and DAA. The impedance is increased to a magnitude such that small fluctuations in the collector (drain) impedance do not vary the over-all electronic inductor circuit impedance. Therefore, as heat generated by the circuit causes the impedance of the transistor in the electronic inductor to change, the impedance change does not adversely affect over-all modem circuit performance.
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Citations
18 Claims
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1. An electronic inductor circuit comprising:
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an input node connected to a telephone line; a ground node; a first transistor device having a first terminal connected to the input node, a second terminal and a third terminal; a second transistor device having a first terminal connected to the third terminal of the first transistor device, a second terminal and a third terminal; a resistor connected between the third terminal of the second transistor device and the ground node; a resistor biasing network connected between the input node and the ground node and to the second terminal of the first and second transistor devices for electrically biasing the transistor devices; and a capacitor connected between the second terminal of the first transistor device and the ground node. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A modem circuit comprising:
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a digital signal processor; a coder/decoder (codec) for interfacing with the digital signal processor; and
a data access arrangement for interfacing the codec with a telephone line, wherein the data access arrangement comprises;voltage isolation means for isolating the the codes from the telephone line; and an electronic inductor, wherein the electronic inductor comprises; an input node connected to the telephone line; a ground node; a first transistor device having a first terminal connected to the input node, a second terminal and a third terminal; a second transistor device having a first terminal connected to the third terminal of the first transistor device, a second terminal and a third terminal; a resistor connected between the third terminal of the second transistor device and the ground node; a resistor biasing network connected between the input node and the ground node and to the second terminal of the first and second transistor devices for electrically biasing the transistor devices; and a capacitor connected between the second terminal of the first transistor device and the ground node. - View Dependent Claims (15, 16, 17, 18)
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Specification