Performing Fine Amplitude Adjustment

When and where to use:

This procedure fine tunes the DSM-II output so the modulation levels (deviation) of all transmitters on a channel are equal for audio.

Procedure:

  1. Set up test equipment. See Setting up Test Equipment.
  2. Set the optimization receiver to monitor the channel under test. Verify that no active carriers are on the channel.
  3. Log in to the TeNSr channel bank of the co-located remote site (or the remote site nearest or co-located to the prime site). This site serves as the reference site.
  4. From the Main window of the DSM-II with the reference port, press the T key to access the Test window.
    NoteThe reference port is the DSM-II port at the reference site that is directly connected to the base radio. The reference port is either a rem, loopback, or sl-lb DSM-II port.
  5. Place the DSM-II reference port for the channel under test into test mode as follows:
    1. Select the desired port by placing the cursor over the TEST field of the desired port. Press Enter.
    2. At the bottom of the window, on and off options appear. Move the cursor over the on option. Press Enter.
    3. Press the S key to save changes. The port under test is now in the test mode.
  6. From the Test window of the reference port, turn on the internal 20 Hz tone as follows:
    1. From the Test window, move the cursor with the arrow keys to highlight the TONE field of the reference port. Press Enter.
    2. At the bottom of the window, off, 1 kHz, 20 Hz, and cal options appear. Move the cursor over the 20 Hz option. Press Enter.
    3. Press the S key to save this change. The port outputs a 20 Hz tone at the Rx output.
  7. From the Test window of the reference port, turn on the E1-Lead to issue a PTT to the base radio as follows:
    1. From the Test window, use the arrow keys to highlight the E1 field of the reference port. Press Enter.
    2. At the bottom of the window, norm, on, and off options appear. Move the cursor over the on option. Press Enter.
    3. Press the S key to save changes. The E1-Lead is enabled for this port.
  8. On the DSA, record the reference value: __________________________, as it is used later.
  9. From the Test window, turn off the internal 20 Hz tone and place the E1-Lead back to normal operation. Turn off the test mode for the reference DSM-II port.
  10. Select and log in to a different remote site TeNSR channel bank.
  11. From the Main window of the DSM-II with the selected port, press the T key to enter the Test window.
  12. Place the DSM-II port for the channel under test into test mode as follows:
    1. Select the desired port by placing the cursor over the TEST field of the desired port. Press Enter.
    2. At the bottom of the window, on and off options appear. Move the cursor over the on option. Press Enter.
    3. Press the S key to save changes. The port under test is in test mode.
  13. From the Test window of the selected port, turn on the internal 20 Hz tone as follows:
    1. From the Test window, move the cursor with the arrow keys to highlight the TONE field of the selected port. Press Enter.
    2. At the bottom of the window, off, 1 kHz, 20 Hz, and cal options appear. Move the cursor over the 20 Hz option. Press Enter.
    3. Press the S key to save this change. The port outputs a 20 Hz tone at the Rx output.
  14. From the Test window of the selected port, turn on the E1-Lead to issue a PTT to the base radio as follows:
    1. From the Test window, use the arrow keys to highlight the E1 field of the selected port. Press Enter.
    2. At the bottom of the window, norm, on, and off options appear. Move the cursor over the on option. Press Enter.
    3. Press the S key to save changes. The E1-Lead is enabled for this port.
  15. Use the DSA to measure the signal at the optimization receiver output.
  16. Note the reference value obtained in 8. Adjust the RX TPL CLR of the selected port until the optimization receiver's discriminator output is equal to the reference value as follows:
    1. In the DSM-II Card window for the selected port, use the arrow keys to highlight the Rx TPL CLR field corresponding to the selected port.
    2. When the desired field is highlighted, press Enter. An entry box appears at the bottom of the window.
    3. Enter a value to adjust the TPL. Press Enter.
      NoteRX TPL CLR range is –16.3 dB to +6.8 dB in 0.1 dB increments.
    4. Press the S key to save the change.
    5. Repeat these substeps until the optimization receiver output value is as close as possible to the reference value.
  17. From the Test window, turn the E1-Lead back to the normal position and turn off the internal 20 Hz tone. Turn off the test mode.
  18. Repeat 10 through 17 for each site on the channel.
  19. Repeat 2 through 18 for each channel in the system.