Abstract: A power supply system includes an a-c. power source and an off-line power supply for storing energy from the a-c. power source during first selected time intervals and converting at least a portion of the stored energy to a d-c. output during second selected time intervals. A diode or other switch disconnects the off-line power supply from the a-c. power source during the second selected time intervals to reduce conducted EMI. The first and second selected time intervals are preferably synchronized to the frequency of the a-c. power source.

Abstract: A product information display system has electronic display tags for displaying pricing and product information for products in stores or warehouses. The electronic display tags are electromagnetically coupled to a conductor. A control circuit is used to generate an information signal which contains a tag address and related data. A modulator circuit modulates an a-c. power signal with the information signal and applies it to the conductor for transmission to the display tags. Each of the display tags is equipped with a coil that is electromagnetically coupled to the conductor for picking up the signals carried by the conductor. A demodulator is used to demodulate the signal picked up by the coil to obtain the original information signal. Each of the display tags is provided with a manually operated switch for initializing the tags with initial addresses transmitted by the conductor.

Abstract: A product information display system has electronic display tags for displaying pricing and product information for products in stores or warehouses. The electronic display tags are electromagnetically coupled to a conductor. A control circuit is used to generate an information signal which contains a tag address and related data. A modulator circuit modulates an a-c. power signal with the information signal and applies it to the conductor for transmission to the display tags. Each of the display tags is equipped with a coil that is electromagnetically coupled to the conductor for picking up the signals carried by the conductor. A demodulator is used to demodulate the signal picked up by the coil to obtain the original information signal. Each of the display tags is provided with a manually operated switch for initializing the tags with initial addresses transmitted by the conductor.