Copyright © Philip M. Parker, INSEAD. Terms of Use.
| Year | Description |
| 2000 | Invention patented by Kazunori Asanaka on January 26th, 2000. Abstract: A DTMF signal generator simplifies frequency characteristic design of a telephone line interface so as to make it easy to carry out alteration of a low tone group frequency component and a high tone group frequency component of a DTMF signal, and to lower cost by doing away with the need for a D/A converter. There are provided first and second sine wave generators (201 and 202) for respectively generating sine waves of specific frequencies, a combining circuit (210) for combining and outputting the outputs of the first and second sine wave generators at a specified ratio, a PWM modulator (214) for generating pulses at a width corresponding to the output of the combining circuit, and a filter (211) for removing undesired frequency components included in the output of the PWM modulator. The combining ratio of the combining circuit is variable. |
| Source: selected by the editor from original sources. | |
Copyright © Philip M. Parker, INSEAD. Terms of Use.
