Voiceband modem control algorithm for improving image quality of mobile telephone facsimile

The authors describe the control algorithm of V.27ter voiceband modem function for improving the image quality of mobile telephone facsimiles and present the results of field experiments to verify the effectiveness of that algorithm. First, impairments unique to the mobile telephone network, in which an analog cellular system is connected with the public switched telephone network (PSTN), are described. Second the impairment of incoming signals mobile telephone facsimile is shown and the key aspects of the voiceband modem control algorithm are described. Finally, the authors show, through experimental results, that the developed modem DSP chip can improve the image quality of mobile telephone facsimile