Extended symbol decoding

An apparatus, comprising:

• a transmitter interface communicatively coupled to a transmitter;
• a memory interface;
• and
• a control circuit communicatively coupled to the transmitter interface and the memory interface, the control circuit to:
• receive, via the transmitter interface, a first PAM symbol group from the transmitter at a first time;
• identify a first path and a second path, the first path and the second path correspond to a state of the transmitter at the first time and each containing at least two symbols;
• store, via the memory interface, a final symbol of the first path and a final symbol of the second path;
• receive, via the transmitter interface, a second PAM symbol group from the transmitter at a second time;
• identify, based on the final symbol of the first path, a third path corresponding to a state of the transmitter at a second time;
• and
• identify, based on the final symbol of the second path, a fourth path corresponding to the state of the transmitter at the second time.

A system, comprising:

• a receiver communicatively coupled to a transmitter via a communication channel;
• a memory;
• and
• a control circuit communicatively coupled to the receiver and the memory, the control circuit to:
• receive, via the receiver, a first PAM symbol group from the transmitter at a first time;
• identify a first path and a second path, the first path and the second path correspond to a state of the transmitter at the first time and each containing at least two symbols;
• store, in the memory, a final symbol of the first path and a final symbol of the second path;
• receive, via the receiver, a second PAM symbol group from the transmitter at a second time;
• identify, based on the final symbol of the first path, a third path corresponding to a state of the transmitter at the second time;
• and
• identify, based on the final symbol of the second path, a fourth path corresponding to the state of the transmitter at the second time.