Baseband amplifier unit and pulse radar device
Provided is a pulse radar device which can attenuate an interference signal and significantly amplify a reflected wave without saturating the interference signal. A baseband amplifier unit ( 5 ) is installed in a pulse radar device ( 1 ) which is configured to transmit from antenna ( 3 ) a transmission pulse wave obtained by modulating a transmission control signal, and to be afterwards switched to a standby mode for a reflected wave obtained by reflecting the transmission pulse wave by an object to be detected. The baseband amplifier unit ( 5 ) includes: a first inverting amplifier ( 52 ) which amplifies the reflected wave; a first switch circuit ( 51 ) which is switched to a cut off state before the transmission control signal rises and is switched back to a conductive state when the transmission control signal falls, to thereby pass through a reflected wave which is input to the first inverting amplifier ( 52 ); and a second switch circuit ( 53 ) which is switched to the cut off state before the first switch circuit ( 51 ) becomes the cut off state and is switched back to the conductive state when the transmission control signal falls, to thereby pass through a signal which is output from the first inverting amplifier ( 52 ).
1. A baseband amplifier unit to be installed in a pulse radar device which is configured to transmit from an antenna toward an object to be detected in a short distance a transmission pulse wave obtained by modulating a transmission control signal, and to be afterwards switched to a standby mode for receiving a reflected wave from the object to be detected, the baseband amplifier unit comprising:
a first amplifier which amplifies the reflected wave;
first switching means for switching the reflected wave to be input to the first amplifier from one of a conductive state and a cut off state to the other state;
second switching means for switching a signal to be output from the first amplifier from one of the conductive state and the cut off state to the other state; and
control means for outputting a first switch control signal for controlling the first switching means to switch to the cut off state before the transmission control signal rises and to switch back to the conductive state when the transmission control signal falls, and for outputting a second switch control signal for controlling the second switching means to switch to the cut off state before the first switching means becomes the cut off state and to switch back to the conductive state when the transmission control signal falls.
2. A baseband amplifier unit according to claim 1 , further comprising:
a second amplifier which amplifies the signal output from the second switching means; and
third switching means for switching the signal output from the second amplifier from one of the conductive state and the cut off state to the other state,
wherein the control means outputs a third switch control signal for controlling the third switching means to switch to the conductive state before the transmission control signal rises and after the first switching means becomes the cut off state, and to switch back to the cut off state with a sufficient time for receiving the reflected wave.
3. A baseband amplifier unit according to claim 2 , wherein the first switching means, the second switching means, and the third switching means operate in the same polarity.
4. A baseband amplifier unit according to claim 2 , wherein the first amplifier and the second amplifier each comprises an inverting amplifier.
5. A pulse radar device, comprising:
a transmitter which generates a transmission pulse wave obtained by modulating a transmission control signal with a high frequency signal and transmits the transmission pulse wave from an antenna toward an object to be detected;
a receiver which detects a reflected wave from the object to be detected that is received by the antenna;
an amplifier which amplifies the reflected wave;
first switching means for switching the reflected wave to be input to the amplifier from one of a conductive state and a cut off state to the other state;
second switching means for switching a signal to be output from the amplifier from one of the conductive state and the cut off state to the other state; and
control means for outputting a first switch control signal for controlling the first switching means to switch to the cut off state before the transmission control signal rises and to switch back to the conductive state when the transmission control signal falls, and for outputting a second switch control signal for controlling the second switching means to switch to the cut off state before the first switching means becomes the cut off state and to switch back to the conductive state when the transmission control signal falls.