Abstract: Methods and apparatus to provide closed loop control in a solar cell production system are disclosed. An example solar cell production system includes: a firing furnace comprising a plurality of zones and a belt configured to transport photovoltaic cells through a sequence of the plurality of zones, the zones comprising firing elements configured to fire a metallization layer of photovoltaic cells by heating ambient air in the zones to respective temperatures; a cooling chamber configured to cool the photovoltaic cells; a photovoltaic cell tester configured to measure a property of the photovoltaic cells after cooling of the photovoltaic cells in the cooling chamber; and control circuitry configured to control firing elements based on the property of the photovoltaic cells measured by the photovoltaic cell tester.

Abstract: A data receiver, which could be an optical transceiver, a modem, a router hub, is capable of detecting the transmission rate of incoming data. The data is converted to electrical waves appropriate for passive or active bandpass filtering. The frequencies at which the waves are filtered are determined from a plurality of known possible transmission rates and are chosen as having the most detectable difference in the power spectra. By implementing a filter at the corresponding frequency(ies), data having that (those) frequency(ies) will be transmitted. A signal detector then can receive a signal transmitted through the filter and determine the corresponding data rate. It is further contemplated that the multiple frequencies can be filtered by using stages of filters and signal detectors for different frequencies or by filters and detectors capable of multiple frequency operation.

Abstract: A data receiver, which could be an optical transceiver, a modem, a router hub, is capable of detecting the transmission rate of incoming data. The data is converted to electrical waves appropriate for passive or active bandpass filtering. The frequencies at which the waves are filtered are determined from a plurality of known possible transmission rates and are chosen as having the most detectable difference in the power spectra. By implementing a filter at the corresponding frequency(ies), data having that (those) frequency(ies) will be transmitted. A signal detector then can receive a signal transmitted through the filter and determine the corresponding data rate. It is further contemplated that the multiple frequencies can be filtered by using stages of filters and signal detectors for different frequencies or by filters and detectors capable of multiple frequency operation.