Patent ID: 7626439

Claim:
A circuit for providing cross-point adjustment comprising: a first input node configured to receive a first data signal; a second input node configured to receive a second data signal that is the complementary of the first data signal; a programmable first stage having a first node coupled to the first input node and a second node coupled to the second input node, wherein the programmable first stage is configured to adjust an amount of current provided to the first or second data signals to thereby create a signal offset, wherein the programmable first stage comprises: a first programmable current supply; a second programmable current supply; a first resistor having a first node coupled to the first input node and a second node coupled to the first programmable current supply; a second resistor having a first node coupled to the second input node and a second node coupled to the second programmable current supply; a first bipolar transistor having a base terminal coupled to the second node of the first resistor and having an emitter terminal coupled to a first current source; a second bipolar transistor having a base terminal coupled to the second node of the second resistor and having an emitter terminal coupled to the first current source; a third resistor having a first terminal coupled to a collector terminal of the first bipolar transistor pair and having a second terminal configured to be coupled to a voltage source when in operation; a fourth resistor having a first terminal coupled to a collector terminal of the second bipolar transistor and having a second terminal configured to be coupled to the voltage source when in operation; wherein the collector terminals of the first and second bipolar transistors act as output nodes; and a second stage having a first node coupled to a third node of the programmable first stage and a second node coupled to a fourth node of the programmable first stage, wherein the second stage is configured to provide the signal offset at a third and fourth node of the second stage to thereby adjust the cross-point of the first and second signals, wherein the first and second input nodes of the cross-point adjustment circuit are coupled to receive the first and second data signals from an amplifying stage of a post-amplifier in a receiver, wherein the third and fourth nodes of the second stage are coupled to adjust the cross-point at an input stage of the post-amplifier; and wherein the first and second programmable current supplies are configured to receive a control signal from a control module specifying the amount of current to adjust, wherein adjusting the first or second programmable current supply causes a signal offset at the collector terminal of the first and second bipolar transistors.