Patent ID: 8693592

Claim:
A receiving device comprising: a variable gain amplifying unit operable to vary a gain based on a gain control value and operable to amplify an input analog signal; an analog-to-digital converting unit operable to convert an amplified analog signal output from the variable gain amplifying unit into a digital signal; a digital signal judging unit operable to judge whether or not the digital signal output from the analog-to-digital converting unit is outside a predetermined range; a preamble start detecting unit operable to detect, from the digital signal output from the analog-to-digital converting unit, a start of a section as a preamble signal which is attached to a head of a wireless packet signal; and a gain control unit operable to control the gain of the variable gain amplifying unit by calculating a gain value to be set in the variable gain amplifying unit and by setting the calculated gain value in the variable gain amplifying unit in accordance with the digital signal output from the analog-to-digital converting unit, wherein the gain control unit controls the gain of the variable gain amplifying unit by performing a first gain control process in which the gain control unit, during a first predetermined time period, repeatedly performs the calculating of the gain value to be set and the setting of the calculated gain value, when the digital signal judging unit judges that the digital signal output from the analog-to-digital converting unit is outside the predetermined range, wherein the gain control unit controls the gain of the variable gain amplifying unit by performing a second gain control process in which the gain control unit, during a second predetermined time period which is shorter than the first predetermined time period, repeatedly performs the calculating of the gain value to be set and the setting of the calculated gain value, when the digital signal judging unit judges that the digital signal output from the analog-to-digital converting unit is not outside the predetermine range and the preamble start detecting unit detects the start of the section as the preamble signal, and wherein the first gain control process and the second gain control process are performed for each packet in the wireless packet signal.