Circuit for settling dc offset in direct conversion receiver
AssigneeMediatek Inc.
InventorsYuan-hung Chung, Chia-hsin Wu, Shou-tsung Wang
Life of this patent
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Abstract
The present invention discloses a circuit for settling DC offset and controlling RC time-constant in a direct conversion receiver. The circuit includes a variable resistive unit for providing a continuously or non-continuously variable resistance in the direct conversion receiver. The variable resistive unit can provide the variable resistance by utilizing a controllable transistor or a plurality of resistors. Accordingly, the variable resistive unit can be coupled to a capacitor for constituting a high pass filter, which is capable of rapidly settling DC offset in a direct conversion receiver.
Claims20
A circuit for settling DC offset in a direct conversion receiver, the circuit comprising:
- a first capacitor having a first end connected to a first input node and a second end connected to a first output node;
- a second capacitor having a first end connected to a second input node and a second end connected to a second output node;
- a first resistor having a first end connected to a bias node and a second end connected to the first output node;
- a second resistor having a first end connected to a bias node and a second end connected to the second output node;
- and
- a variable resistive unit having a first end connected to the first output node and a second end connected to the second output node.
A circuit for settling DC offset in a direct conversion receiver, comprising:
- a voltage node for receiving a bias voltage;
- a couple of input nodes for receiving a differential signal pair;
- a couple of output nodes for outputting an output signal pair generated by the circuit;
- a couple of resistors for protecting the circuit from overloading, each having a first end connected to the voltage node and a second end connected to the corresponding output node;
- a couple of capacitors, each having a first end connected to the corresponding input node and a second end connected to the corresponding output node;
- and
- a variable resistive unit for providing an equivalent resistance, which is connected between the couple of the output nodes.
Dependencies are inferred from the claim text.