| 摘要 |
The communications system uses both PFM and PDM signals. The signals are modulated onto an ac carrier which is transmitted inductively. The frequency of the PFM modulation is determined both by the time width of the ac pulses and by the width of the intervals between pulses. The pulse width is determined only by the width of the ac pulses. The width of the ac pulses and of the pulse intervals is an integral multiple (pref. an even multiple) of the ac halfwave. Current pulses switch the ac current source on and off. |
