% OPMODE denotes the operation mode of the decoder. Choices are: % 'trunc' : The encoder is assumed to have started at the all-zeros state. % The decoder traces back from the state with the best metric. % 'term' : The encoder is assumed to have both started and ended at the % all-zeros state. The decoder traces back from the all-zeros % state. % 'cont' : The encoder is assumed to have started at the all-zeros state. % The decoder traces back from the state with the best metric. A % delay equal to TBLEN symbols is incurred.

这是一段MATLAB程序的注释，描述了一个语音编解码器的操作模式。OPMODE是一个变量，用来指定解码器的操作模式，可以取三个值：'trunc'，'term'和'cont'。'trunc'模式下，解码器假设编码器从零状态开始工作，从最佳度量状态进行回溯；'term'模式下，解码器假设编码器从零状态开始且在零状态结束，从零状态进行回溯；'cont'模式下，解码器假设编码器从零状态开始工作，从最佳度量状态进行回溯，并且需要延迟TBLEN个符号的时间。这三种模式可以用于不同的解码应用场景，以满足对不同语音数据的解码需求。