RECEIVED SIGNAL GAIN CONTROL METHOD AND RADIO FREQUENCY SIGNAL RECEIVING APPARATUS
A radio signal receiving apparatus receiving a radio signal over a radio channel generates a first amplified signal by amplifying the radio signal with a first gain, and determines the first gain by measuring the strength of the first amplified signal. In addition, the radio signal receiving apparatus generates a down-converted signal by frequency down-converting the first amplified signal, and generates a second amplified signal by amplifying the down-converted signal with a second gain. In addition, the radio signal receiving apparatus determines the second gain by measuring the strength of the second amplified signal.
1 . A radio signal amplifying method comprising:
generating a first amplified signal by amplifying a radio signal with a first gain;
determining the first gain by measuring the strength of the first amplified signal;
frequency down-converting the first amplified signal for generating the down-converted signal;
generating a second amplified signal by amplifying the down-converted signal with a second gain; and
determining the second gain by measuring the strength of the second amplified signal.
2 . The radio signal amplifying method of claim 1 , wherein the generating the first amplified signal comprises amplifying the radio signal through a plurality of amplifiers, and the determining the first gain comprises determining turn-on/turn-off of each of the respective amplifiers according to the first gain.
3 . The radio signal amplifying method of claim 2 , wherein the determining the first gain further comprises measuring the strength of the first amplified signal in the state of an analog signal.
4 . The radio signal amplifying method of claim 1 , wherein the determining the second gain comprises:
measuring a strength difference value between the strength of the second amplified signal and the strength of a second amplified signal at a previous time;
generating the second gain according to the strength difference value when the strength difference value is greater than a reference value; and
maintaining the second gain at a level of the second gain of the previous time when the strength difference value is smaller than the reference value.
5 . The radio signal amplifying method of claim 4 , wherein the generating the second gain further comprises setting a time interval for measuring the strength of the second amplified signal with an initial value.
6 . The radio signal amplifying method of claim 4 , wherein the maintaining the second gain at the level of the second gain of the previous time further comprises setting a time interval for measuring the strength of the second amplified signal to be longer than the present time interval.
7 . The radio signal amplifying method of claim 4 , wherein the determining the second gain further comprises measuring the strength of the second amplified signal in the state of a digital signal.
8 . A radio signal receiving apparatus comprising:
an amplifying end for generating a first amplified signal by amplifying a radio signal with a first gain;
a first strength measurer for measuring the strength of the first amplified signal;
a first power controller for determining the first gain according to the strength of the first amplified signal;
a mixer for generating a down-converted signal by frequency down-converting the first amplified signal;
an amplifier for generating a second amplified signal by amplifying the down-converted signal with a second gain;
a second measurer for measuring the strength of the second amplified signal; and
a second power controller for determining the second gain according to the strength of the second amplified signal.
9 . The radio signal receiving apparatus of claim 8 , wherein the amplifying end comprises:
a plurality of amplifiers respectively amplifying an input signal with each gain and outputting an amplified signal; and
a plurality of switches respectively determining turn-on/turn-off of each of the plurality of amplifiers.
10 . The radio signal receiving apparatus of claim 8 , wherein the first power controller applies an on-off control signal to the plurality of switches that are respectively connected with the plurality of amplifiers according to the first gain.
11 . The radio signal receiving apparatus of claim 8 , wherein the first strength measurer measures the strength of the first amplified signal in the state of an analog signal.
12 . The radio signal receiving apparatus of claim 8 , further comprising a converter for converting the second amplified signal from an analog format to a digital format.
13 . The radio signal receiving apparatus of claim 12 , wherein the second strength measurer measures the second amplified signal in the state of a digital signal.
14 . The radio signal receiving apparatus of claim 8 , wherein the second power controller generates the second gain when a strength difference value between the second amplified signal and a second amplified signal of the previous time is greater than a reference value.
15 . The radio signal receiving apparatus of claim 14 , wherein the second power controller sets a time interval for the second strength measurer to measure the strength of the second amplified signal with an initial value when the strength difference value is greater than the reference value.
16 . The radio signal receiving apparatus of claim 8 , wherein the second power controller maintains the second gain at a level of a second gain of a previous time when a strength difference value between the second amplified signal and a second amplified signal of the previous time is smaller than a reference value.
17 . The radio signal receiving apparatus of claim 16 , wherein the second power controller sets a time interval for the second strength measurer to measure the strength of the second amplified signal to be longer than a time interval of the present time when the strength difference value is smaller than the reference value.
18 . The radio signal receiving apparatus of claim 8 , further comprising a control signal generator for generating a control signal that changes a gain resistance of the amplifier according to the second gain.