RF RECEIVER CAPABLE OF VARYING GAINS OF AMPLIFIERS CONFIGURING LIMITER AND CHANGING THE GAIN IN INVERSE PROPORTION TO THE AMPLITUDE OF INPUT SIGNAL

摘要

PURPOSE: An RF receiver is provided to vary gains of amplifiers configuring a limiter, and to change the gain in inverse proportion to the amplitude of an input signal, thereby reducing current consumption and a layout size without using a smoothing filter while maintaining a certain size of an output signal. CONSTITUTION: A limiter(20) includes variable gain amplifiers(21-24) whose gains are controlled by 4-bit RSSI signals. An RSSI circuit(30) comprises as follows. A rectifier(31) extracts the size of an input value. A comparator(32) compares the extracted size of the input value with reference values. An RSSI encoder(33) outputs the RSSI signals by using results outputted from the comparator(32). The RSSI signals outputted from the RSSI encoder(33) are applied to resistant arrays of the variable gain amplifiers(21-24) without passing through other conversion, and vary the gains of the amplifiers(21-24).