| 摘要 |
<p>PURPOSE: To demodulate accurately a multi-value level signal by controlling an amplification factor so that a difference between a maximum voltage and a minimum voltage is kept always constant. CONSTITUTION: I-group m-sets of data (binary n-bit data per one data) are converted into (m+1)-sets of signals in total at a multi-value level where one basic period consists of m-sets of time slots (0th to (m-1)th) levels in total consist of 0th to (m-)th levels and an upper reference level. The basic period is a class A basic period and a class B basic period. Index data at a prescribed position for one group are used for Tth slot signal depending on a value T, 0-level signal for the class A basic period and are upper reference level signal for the class B basic period. Usual data are converted into other slot sequentially, the signal for the class A basic period is converted into a signal having a level Lj +1 to shift the level Lj by one level higher, and the signal for the class B basic period is converted into a signal with a level Lj . In this system, a minimum voltage for the class A basic period in the multi-value level signal and the maximum voltage for the class B basic period are detected to change the amplification factor of a gain control amplifier so that the voltage difference is constant.</p> |
