Checking Calibration and Dynamic Range

Test Goal

Verify the receiver dynamic range is in excess of 80 dB.

Caution This test requires the injection of an RF test signal over a 100 dB range. Damage to the LNA could occur. Check the LNA specification to verify the maximum signal that it can accept. The do not allow the output from the signal generator (accounting for cable and coupler losses) to exceed this value.

Caution To avoid damage to IFDR10, do not increase the signal generator power such that the Total Power exceeds the Safe Total Power Limit for the Pr command display more than +12dBm.

Test Equipment

KVM connected

RF signal generator

Test Procedure

1. Run the radar and test signal generator for 20 minutes to allow proper warm-up of the system prior to the test.

   This allows the AFC to stabilize.

2. Turn the radiate off, but leave the receiver on since the test signal generator may be damaged by the transmitter.

3. Elevate the antenna to >20° and point the azimuth away from any known microwave sources including the sun.

4. Use the setup terminal to enter the calibration gains, losses, and transmit power values.

5. Enter the TTY setups through dspx.

6. Use the ps command in the dspx utility to put RVP10 in manual AFC control by pressing = .

7. Connect the test signal generator to inject a signal at RF ahead of the LNA.

8. Press % to select the IF input under test.

9. Set the signal generator to a value that is approximately 20 dB above noise and observe the scope plot.

10. Adjust the frequency of the test signal generator to make the frequency of the spectrum to the correct IF frequency.

    You can also do this by using Pr to monitor the Filtered reading and selecting the frequency setting with the highest dBm reading.

    Filtered: ________dBm

11. Open the ZAUTO utility and perform a calibration:
    1. Begin at +10-dBm and decrease the SIGGEN power by 10 dB for each sample.
    2. At the saturation point and noise floor use 1 dB steps to carefully define the roll-offs.
    3. Select the lower and upper bounds of the linear portion of the receiver.
    4. Select FIT.
    5. Turn off the SIGGEN RF output and select NOISE.
    6. Verify that the receiver dynamic range is greater than or equal to 95 dB.
    7. Check that the signal generator frequency has not drifted by looking at the plot.
    8. If it is off by more than 0.1 MHz, retune and repeat the test.
12. In the dspx utility, put RVP10 back in automatic AFC control by typing the ps command and pressing =.
13. Record RVP10 calibration values.

Checklist