Systems, methods, and devices for enforcing do not disturb functionality on mobile devices
摘要
說明書
In another implementation, instead of feeding the received RF signal into a splitter and combiner, a switch is used. This mitigates the poor SNR of the previous approach, but at the cost of greater complexity as logic is required to control the switches. In addition, timing constraints now exist on when the power detector output is valid. Also, because all bands are not monitored constantly (if a single antenna is being used), short uplink pulses may be missed (e.g., sending of a text message on one band while another band is being monitored).
In another implementation, the RF signal is routed from the antenna to a mixer. The mixer is also connected to a voltage-controlled oscillator (VCO). By controlling the VCO, the signal can be frequency-shifted. An advantage of shifting the received RF signal around is the ability to use a single filter. The bandwidth of the filter is chosen to be the bandwidth of the narrowest noncontiguous band to be detected. Wider bands are swept across in multiple steps. This approach has low attenuation and allows identifying the band of the signal. However, complexity is high as logic is required to control the switches and timing constraints now exist on when the power detector output is valid. Also, because all bands are not monitored constantly, short signals may be missed. A second implementation with the mixer and VCO includes shifting the received RF signal to a lower frequency for less hardware intensive analysis. With the RF signal shifted downward, Fourier Transforms and Inverse Fourier Transforms can be computed and processed with minimal delay.
