| 摘要 |
A communication information signal from a portable radiophone is concurrently decoded by two decoder units to decode data and voice signals. A data signal portion of the information signal is decoded by a data decoder and then a data signal sensor decides whether or not the decoded signal is a normal data signal. Only the normal signal is fed to a signal converter to conduct a code conversion. The resultant signal is outputted from a transmitter circuit. On the other hand, a voice signal portion of the information signal is decoded by a voice decoder and then a voice signal sensor determines whether or not the decoded signal is a normal voice signal. Only the normal signal is sent to a digital-to-analog converter to be transformed into an analog voice signal. Validity of the decoded signal is verified according to, for example, variation in a frequency band and/or amplitude of the decoded signal. Due to the concurrent decoding operation, data and voice signals are efficiently decoded by one modem card at a high speed. There is hence configured a modem card for a portable radiophone capable of concurrently sending data and voice signals to the information terminal.
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