| 摘要 |
PURPOSE: To facilitate demodulation and shorten a frame transmission period TF by imposing pulse phase modulation in units of 2-bit data. CONSTITUTION: When the 2-bit data is (0, 0) in normal mode, a pulse signal with pulse width (t) is generated and a pulse stop interval Tr is set to the pulse width (t). When the data is (0, 1), a pulse signal with pulse width (t) is generated to set the interval Tr to 2t, and when the data is (1, 0), a signal with pulse width (t) is generated to set the interval Tr to 3t. When the data is (1, 1), the rear interval Tr of a pulse signal with pulse width (t) is set to 4t. Further, the 2-bit data (0, 0) of a flag is set similarly to an interval equal to the pulse width (t) after a pulse signal with the pulse width (t) is generated, and is modulated into a flag signal. Before that, a header, a flag signal, and then an end signal are applied to obtain a 2-bit PPM modulated signal. Consequently, the demodulation is facilitated and the frame transmission period TF is shortened. |
