Electronic devices with frequency scan acceleration

A method of operating wireless circuitry, the method comprising:

• receiving, using a radio, radio-frequency signals;
• converting, using the radio, the radio-frequency signals into baseband signals;
• generating filtered baseband signals by applying a bandwidth filter to the baseband signals;
• switching the bandwidth filter between different bandwidth configurations over time;
• outputting, using one or more processors, a different respective autocorrelation metric based on the filtered baseband signals that are generated while the bandwidth filter exhibits each of the different bandwidth configurations;
• performing, using the radio, a search for a wireless base station based on the different respective autocorrelation metrics;
• and
• establishing, using the radio, a link with the wireless base station in response to the search detecting a signal transmitted by the wireless base station.

A method of operating wireless circuitry, the method comprising:

• receiving, using a radio, radio-frequency signals;
• converting, using the radio, the radio-frequency signals into baseband signals;
• generating first filtered baseband signals by applying a bandwidth filter to the baseband signals while the baseband filter has a first bandwidth configuration;
• generating second filtered baseband signals by applying the bandwidth filter to the baseband signals while the baseband filter has a second bandwidth configuration that is different than the first bandwidth configuration;
• outputting, using one or more processors, a first autocorrelation metric based on the first filtered baseband signals;
• outputting, using the one or more processors, a second autocorrelation metric based on the second filtered baseband signals;
• performing, using the radio, a search for a wireless base station over a set of candidate frequencies that is selected based on a higher of the first autocorrelation metric and the second autocorrelation metric;
• and
• establishing, using the radio, a link with the wireless base station in response to the search detecting a signal transmitted by the wireless base station.