| 摘要 |
PURPOSE:To detect the level of a digital sine wave through simple circuit constitution which eliminates the need for a filter by adding the square value of the result of subtraction of a signal output which is 2m samples before from an input sine wave to the square value of the result of subtraction of a signal output which is (m) samples before. CONSTITUTION:A sine wave is inputted to an input terminal 10 and a signal which is (m) samples before is outputted by a delay circuit 1. Further, a delay circuit 2 delays the output by (m) samples to output a signal which is 2m samples before. A subtracter 3 outputs the difference 40 of the signal which is 2m samples away. The difference 40 is squared by a squaring device 4 and the output 20 of the circuit 1 is squared by a squaring device 5. The outputs of the squaring devices 4 and 5 are summed up by an adder 6, which outputs the square value of the maximum level of the input digital sine wave to its output terminal 70. This simple hardware constitution provides accurate level detection. |
