According to one embodiment, a receiver includes: a reception analog circuit, a frame detector, and a controller. One mode among a plurality of modes can be selected for the reception analog circuit. Power consumption is different depending on the modes. The reception analog circuit is configured to process an analog signal received by an antenna to generate a digital signal with first accuracy depending on the selected mode. The frame detector is configured to detect a first frame from the digital signal. The controller is configured to make the reception analog circuit operate on a first mode among the plurality of modes until the first frame is detected and make the reception analog circuit operate on a second mode among the plurality of modes after the first frame is detected. Power consumption of the second mode is higher than power consumption of the first mode.