Received signal strength measurement circuit, received signal strength detection circuit and wireless receiver

Abstract

The RSSI circuit of the present invention includes: an IF amplifier section, which includes multiple stages of serially connected differential amplifiers for amplifying, with use of a current source IA provided as a power source for amplification, an IF signal corresponding to a received signal; an RSSI amplifier section for converting into current a voltage amplitude of an absolute value signal outputted from the differential amplifiers of the IF amplifier section, using a current source IB provided as a power source for conversion, and adding and outputting the converted current; and a current voltage conversion circuit for converting into voltage the output current from the RSSI amplifier section, and outputting the converted voltage as a measurement voltage value. The RSSI amplifier section is set so that a current value of the RSSI amplifier section is inversely proportional to absolute temperature. With the configuration, it is possible to realize an RSSI circuit, a received signal strength detection circuit and a wireless receiver, which are able to stabilize a strength measurement of a received signal relative to a change in temperature and to increase communication characteristics.

Description

technical field [0001] The present invention relates to a received signal strength measuring circuit (generally referred to as an RSSI circuit), a received signal strength detecting circuit, and a wireless receiver using the same, which are used in a wireless receiving device and have excellent temperature stability. Background technique [0002] In a wireless receiver, generally, a high-frequency wireless signal obtained from an antenna is first converted into an intermediate frequency signal (IF signal), and then the intermediate frequency signal is amplified and input to a detector. Desired processing, that is, detection processing for extracting information contained in the wireless signal is performed in the detector. In this detection process, the amplification factors of the wireless signal and the intermediate frequency signal are set in accordance with the signal strength of the radio wave received by the wireless receiver so as to be within a range suitable for per...

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Problems solved by technology

[0014] In this way, there is a problem in the conventional RSSI circuit system: because the temperature dependence of the output amplitude (gain) varies greatly with the input level to the intermediate frequency amplifier circuit 1220 Similarly, output characteristics vary depending on temperature, which can be a major cause of error

[0015] In the above-mentioned prior art, there are still the following problems: In order to improve the temperature dependence of this output, the conversion circuit 1240 is required, so that the entire circuit is composed of numerous and diverse; the RSSI circuit When the system is built into the LSI, it is also necessary to incorporate the occupied area for the conversion circuit 1240, which hinders the miniaturization and high integration of the circuit; the conversion circuit 1240 increases the current consumption

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