Systems, devices and methods related to improved radio-frequency modules. The high-frequency amplifier is configured such that an RF signal having n frequencies applied to the amplifier is converted by an impedance conversion circuit to a higher impedance than the output impedance of the amplifier, and is branched into the highest frequency f1 and lower frequencies lower than that by a high-pass filter and a low-pass filter. Via this configuration, an output signal from a detector detecting a reflected light via a side beam, that is, a signal representing a different in the output from photo-detection devices split by split lines in the radial contains a negligible track cross component caused by a beam spot crossing a track. For example, the purchase history of other members of the cluster may be analyzed to determine whether other members purchased a particular size of the item, and if so, the size purchased by the other members may serve as a basis to recommend a size that may best fit the consumer. The induction part includes an outdoor air induction port, a lower guide member to guide air current induced from the outdoor air induction port, a purification cartridge, a light-transmission portion, and a purified air discharge port.