PA LNA duplexer usage
1. connection:
my PA LNA typically is a integrated product.
For FDD PA LNA:
PA IN port connect to usrp TX port;
PA OUT port connect to duplexer TX port;
LNA OUT port connect to usrp RX port;
LNA IN port connect to duplexer RX port;
duplexer ANT port connect to antenna;
For TDD PA LNA it don't need duplexer:
PA IN port connect to usrp TX port;
LNA OUT port connect to usrp RX port;
ANT port connect to antenna;
reference picture below
for the power cable and control cable there is mark on the PA LNA product.
in below picture there are two column mark near the connected cable, the cable have two rows. the left column mark means the top row of the cable and the right column mark means the bottom row of the cable. in this picture 28v is the red cable, GND is the black cable under the red cable, TX is the green cable, RX is the brown cable under green cable, 485B is the blue cable, 485A is the gray cable under the blue cable. typically if the PA is for FDD you only need to connect the power cable that is 28v and GND, if the PA is for TDD then you also need to use TX pin. TX pin is used to toggle the PA downlink and uplink status. Pull TX pin high will turn the PA at downlink status which means PA is on and LNA is down. Pull TX pin low will turn the PA at uplink status which means PA is down and LNA is on. the control cable is used for setting the gain or other parameter, and that is already set well before shipment.
2. cable
the sma cable for large power PA LNA need to use the semi-rigid or semi-flexible cable. because it provide enough isolation for the large power PA LNA. for PA LNA power larger then 10w we suggest use at least semi-flexible cable. and for large power PA LNA the large power part need to use thick cable rather than thin cable because the large power signal will have larger currency, if use thin cable will very hot. if you are using large power PA LNA the cable connect to PA OUT port and ANT port need to use the thick sma cable, and for other port can use thin sma cable.
below is the picture of the thick and thin semi-flexible sma cable. we will provide suitable cable for large PA LNA product.
3. heat sink
the PA LNA product need heat sink. use how large heat sink need to depend on your environment. the PA LNA bottom is usually stick on heat sink like the first picture of this thread. you need to make sure the PA product temperature is under its working temperature(typically 65℃, but better under 50℃). if you can not provide enough large heat sink you can add fans.
if you need to put the PA LNA product in a sealed case then you need to use the case like below picture. this case is heat sink it self.