| 摘要 |
PURPOSE:To prevent malfunction by providing an encoding circuit with a decision level transmitting circuit, and comparing an input decision level with a voice level from an A/D converter and stopping the output of an up/down signal transmitting circuit when a sampled value is greater than the decision value. CONSTITUTION:A voice waveform from an input terminal 10 is sampled by an A/D converting circuit 1 to convert the waveform into a digital signal, which is latched by a latch circuit 3. The last sampling output of the circuit 3 is compared by a comparing circuit 4 with the output of the circuit 1 and their difference data is compressed by a difference data compressing circuit 5 according to the level of an adequate level transmitting circuit 7. The output of the circuit 5 is applied to an up/down signal transmitting circuit 8 and the outputs of the circuits 7 and 8 are summed up by an adding circuit 6 to control the circuit 7 by the output of the circuit 6. A decision level transmitting circuit 9 is added to this encoding circuit to compare a decision level from an input terminal 13 with the voice level from the converter 1, thereby stopping the output of the circuit 8 when the sampled value is greater than the decision level. |
