Single-Turn Absolute Value Encoder and Multi-Turn Absolute Value Encoder are two common types of position encoders used to encode input position information into vector representation, and they have some differences in their operating principles.

Single-Turn Absolute Value Encoder：
A single-turn absolute value encoder uses a scaled angle value to represent a specific position. Typically, it maps a fixed range of positions to a continuous range of values. For example, it may map positions from 0 to 360 degrees to a continuous range from 0 to 1. The main advantage of this encoder is its simplicity and ease of implementation. However, it can only represent the position information of a single turn and cannot differentiate between multiple positions at the same angle.

Multi-Turn Absolute Value Encoder：
A multi-turn absolute value encoder adds extra information to track multiple rotations. It uses a modulo operation on the input position to find complete rotations, then employs a single-turn absolute value encoder for each rotation’s position. For example, it could use a binary vector for turn count, map the current position to a value from 0 to 1, and combine this with the binary turn vector. This method distinguishes between identical angles, enhancing position representation.

In summary, a single-turn absolute value encoder is suitable for representing position information with only one turn, while a multi-turn absolute value encoder is suitable for distinguishing position information across multiple turns. The key to choosing the encoder lies in the requirements of the positional information and understanding the application scenarios of the model.