Active termination network

A transmission line termination circuit for terminating a transmission line having a first end where a signal enters the transmission line and a second end where the signal exits the transmission line, said transmission line having a characteristic impedance of 50 ohms, said transmission line termination circuit comprising:

• a connection to the second end of said transmission line;
• a terminating impedance connected to the second end of the transmission line through said connection, said terminating impedance comprising an active impedance and a 25 ohm resistor connected in series;
• and
• a control circuit for controlling an impedance of said active impedance in response to the signal on the transmission line in order for the terminating impedance to substantially match the characteristic impedance of the transmission line, such that the terminating impedance varies between approximately 48 and 53 ohms while voltage across the 25 ohm resistor changes by approximately 0.6 volts, said control circuit comprising a peak detector for generating a compare voltage in response to the signal on the transmission line.