| 摘要 |
PURPOSE:To measure the noise margin of digital transmission system, by providing the pulse sequence generating means, variable pulse inserting means, pulse position changing means, means altering the parameter for variable pulse, and shift value integrating means. CONSTITUTION:When the pulse sequence is transmitted via the simulator 10, the output sequence is subjected to attenuation, and the interference between codes (ISI) is applied to the output sequence by keeping the transmission cable in the same state as itself. The pulse in this sequence passes through the generator under test and reaches the coupling data input amplifier/clock recovery circuit 36 via the 1st transformer 14, 2nd transformer 18 and line 16. The clock signal is recovered in this circuit and the amplification at the signal given with the pulse sequence is made to forward the output of positive and negative to HDB3 and decoder 28. The output of the decoder 38 is equal to the pattern of the generator 20 when no error. |
