| 摘要 |
PURPOSE:To measure the input and output characteristics of a decoder which does not respond to DC input by measuring the input and output characteristics of the decoder by using the sine waves, etc. of specific frequencies, and arbitrary input signal waveform. CONSTITUTION:Digital sine waves are generated from a digital signal generating circuit 10. The frequency thereof is set in the pass area of the last filter of a decoder (DUT) 2 to be measured. An output fetching select circuit 4 detects the position where the patterns generated by the circuit 10 assumes a specific code, fetches the analog output of the DUT2 corresponding to said input, transmits the same to a level measuring circuit 3, and interrupts the analog outputs corresponding to other codes. The response of the circuit 3 is usually slow as compared to the conversion period of the DUT2, and therefore, in the circuit 3 the analog outputs past the circuit 4 are integrated, whereby level detection is carried out, and the processing similar to the level detection of DC input is accomplished. |
