To Make A 12 Db Sinad Measurement; To Test Your Transmitter - HP 8921A User Manual

Chapter 10, Signaling Encoder (AF Generator 2)
Using the LTR Encoder
348

To make a 12 dB SINAD measurement

1. Set Filter 1 to 300Hz HPF and Filter 2 to 3kHz LPF.
2. Decrease the Amplitude until approximately 12 dB SINAD is displayed.
3. Use the AVG (average) function to stabilize the measurement by positioning the cursor
in front of the SINAD dB field and pressing and releasing the SHIFT key, then the
INCR 10 key to access the AVG function, then press the ENTER key.

To Test Your Transmitter

To establish a trunked transmit channel on the home channel:
1. Connect the RF IN/OUT port of the Test Set to your radio's antenna port.
2. Turn your radio on, and select the channel to test.
3. Press the PRESET key (to establish a known instrument state for this procedure).
4. Access the DUPLEX TEST screen.
5. Set the Tune Mode field to Manual.
6. Enter the home channel's transmit frequency in the Tune Freq field.
7. Enter the home channel's receive frequency in the RF Gen Freq field.
8. Set AFGen1 To to Off.
9. Set the AF Anl In field to FM Demod.
10. Access the ENCODER screen, and select the LTR mode.
11. Set up Message 1 with idle message data:
a. Enter your Area Number (0 or 1) in the Area 1 field.
b. Enter the home channel number in these fields: Goto 1, Home 1, and Free 1.
c. Enter 255 in the ID 1 field to establish an idle channel.
12. Set up Message 2 with transmit message data:
a. Enter your Area Number (0 or 1) in the Area 2 field.
b. Enter the home channel number in these fields: Goto 2, Home 2, and Free 2.
c. Enter the Transmit ID number for your radio in the ID 2 field.
13. Set the Send Mode field to Cont.
14. Set the AFGen2 To field to FM, 1 kHz.
15. Set the FM Coupling field to DC.
16. Set the LTR message field to Message1.
17. Select Send to continuously output idle message.
18. Key the transmitter.
19. Select Message2 in the LTR message field to tell your radio to transmit. If the
transmitter fails to establish a transmit channel before time-out occurs, try again using
these steps:
a. De-key the transmitter.
b. Select Message 1.
c. Key the transmitter.
d. Select Message 2.