| 摘要 |
PURPOSE:To increase the margin to line distortion of a reception signal received from a line and to make the system suitable for numerical operation processing by providing the uniform margin to each discriminating area in a direction of phase angle and giving a constant error rate to the amplitude in the amplitude direction within a possible range. CONSTITUTION:Normal demodulation is applied to a transmitted signal by a demodulator and a reception signal point (x1, y1) is outputted. After a corresponding phase angle is obtained from the signal point (x1, y1) at a phase discrimination circuit, the amplitude is discriminated by an amplitude discrimination circuit and an area belonging to the signal point is decided. The margin to noise is made constant by dividing the area with boundary lines making the rate of the distance extending from a reference point to a signal point to the distance extending from the origin to a reference point, constant and the area is approximated by a circle having the center at the origin taking the circuit scale and processing speed into account. Then the distance extending from the origin to the signal point is calculated and the discrimination is attained with the radius of the circle, that is, the reference value. |
