TESTING DEVICE FOR OPERATION OF SPEAKER

摘要

PURPOSE: To surely and accurately judge the operation of a speaker by easily measuring the impedance of the speaker. ;CONSTITUTION: A constant current signal Sa of a constant current in an audio range is sent out of a constant current output circuit 2 to the speaker as an object of an operation test and a BPF 3. Constant currents Sa (Sa1, Sa2, and Sa3) of level, varied on the basis of the impedance of the speaker, from the BPF 3 are set to a specific level through a variable amplification part 4 and a speaker impedance switching part 5, and further detected by an effective value measuring circuit 9 and converted into a DC level, which is compared by an abnormality detecting circuit 10 with a previously set threshold value. When the DC level exceeds the threshold value, the abnormality detecting circuit 10 displays abnormal operation such as a open circuit and a short circuit of the voice coil path of the speaker by the illumination or blinking, a figure or character screen display, or a sound or synthesized voice or their combination through a display circuit 14.;COPYRIGHT: (C)1995,JPO