ERROR RATIO MEASURING INSTRUMENT AND ERROR-RATIO MEASUREMENT RECORDING MEDIUM

PROBLEM TO BE SOLVED: To measure an error ratio in a short time and to accelerate the quality display of data transmission by successively switching plural counters which have carry values that are mutually different and using a small carry value, when an error ratio increases. SOLUTION: Cyclic counters 11 to 13 count the number of bits which are synchronized with transmission data based on repeating cycles that are mutually different, and a counter selector 14 selects one from among plural these count results according to selector information and transfers a carry signal of the counter. An error-counting part 20 accumulates error bit numbers in digital data which is divided into plural samples, introduces a carry signal from the selector 14 and sends an error accumulation value at that time. Further, an error-ratio deciding part 30 calculates an error ratio by dividing an error accumulation value by a counted maximum value, show it and also switches it to a value that has a different repeating cycle, when the error accumulation value reaches a prescribed value.