Methods and apparatus to transmit a serial data stream

An apparatus comprising:

• receiver circuitry having an input;
• transmitter circuitry having a first output, a second output, a third output, and a fourth output;
• and
• echo cancelation circuitry including:
• load circuitry having a first input, a second input, a first output and a second output, the first input of the load circuitry coupled to the first output of the transmitter circuitry, the second input of the load circuitry coupled to the second output of the transmitter circuitry;
• and
• combination circuitry having a first input, a second input, a third input, a fourth input, and an output, the first input of the combination circuitry coupled to the third output of the transmitter circuitry, the second input of the combination circuitry coupled to the fourth output of the transmitter circuitry, the third input of the combination circuitry coupled to the first output of the load circuitry, the fourth input of the combination circuitry coupled to the second output of the load circuitry, the output of the combination circuitry coupled to the input of the receiver circuitry.

An apparatus comprising:

• first transmitter circuitry having an output;
• a communication channel having a first terminal and a second terminal, the first terminal of the communication channel coupled to the output of the first transmitter circuitry;
• second transmitter circuitry having a first output and a second output;
• echo cancelation circuitry having a first input, a second input, and an output, the first input of the echo cancelation circuitry coupled to the first output of the second transmitter circuitry, the second input of the echo cancelation circuitry coupled to the second terminal of the communication channel and the second output of the second transmitter circuitry;
• and
• receiver circuitry having an input coupled to the output of the echo cancelation circuitry.