| 摘要 |
PURPOSE: An apparatus for adjusting a receiving band in a radio transmit-receive system is provided to enhance signal regeneration by increasing the dynamic range of a receiving path and improving the demodulation capability of a receiving unit, in a system that executes the modulation and demodulation of a digital signal. CONSTITUTION: An apparatus for adjusting a receiving band in a radio transmit-receive system is composed of a multiplexer(21), an AGC part(30), the second LNA(Low Noise Amplifier)(22), the first BPF(Band Pass Filter)(23), a frequency conversion part(24,25), the second BPF(26) and a demodulator(27). The multiplexer(21) multiplexes a signal transmitted or received through an antenna. The AGC part(30), adjusting the gain of a signal received through the antenna, is comprised of a power detector(31) and the first LNA(32). The power detector(31) detects the strength of the received signal. The first LNA(32) adjusts the gain of the received signal, based on the detected signal strength. The second LNA(22) executes low noise amplification for the gain-controlled received signal outputted from the AGC part(30). The first BPF(23) filters a receiving-band signal among the signals outputted from the second LNA(22). The frequency conversion part(24,25) converts the signal filtered through the first BPF(23) into an IF(Intermediate Frequency) signal. The second BPF(26) filters the IF signal. The demodulator(27) demodulates the signal outputted from the second BPF(26), based on the modulation type of the signal.
|
