RDS P232U, Быстрое руководство по установке, Страница: 9 / 15

9
3.5 RDS Level Adjustment
Important note: There is no universal setting for the RDS level. Due to different input sensitivity of various FM broadcast equipment it's
necessary to check and adjust the RDS level each time you connect a new FM transmitter to the RDS encoder!
The correct level should be between 2 and 11 % of the audio multiplex signal, measured by oscilloscope in peak-to-peak values on the
modulator input. Recommended value is such that results in 3.4 kHz deviation of the FM carrier. Don’t forget that the maximum total FM carrier
deviation with RDS and MPX signal is 75 kHz. It is much easier to use an FM broadcast analyzer for setting the RDS level precisely.
The RDS level can be adjusted after establishing a connection to the encoder, using one of these two methods:
In the Windows software
The control is available in Device Setup section, page Analog Control.
Enter the RDS level directly in mV p-p unit or check the ‘Track’ box and adjust the level as desired. Finally confirm by the Apply button.
In terminal, using ASCII command LEVEL=
The P232U RDS encoder allows direct adjusting of the RDS level in 256 steps, in range 0 to 255, by assigning a corresponding value to the
LEVEL parameter. Each step represents approx. 15.6 mV increase.
Desired step count can be calculated as
1
4000
256







 
level RDS Output
LEVEL
Actual output RDS level (in
mV p-p ) can be calculated as
4000
256
1



LEVEL
level RDS Output
3.6 Low Power Operation
Although the RDS encoder’s power consumption is usually negligible compared to the FM transmitter, there are some tips how to reduce it
furthermore:

Using 9 V power supply instead of 12 V
Saves about 25 % of energy. This option is applicable only if the analogue signal (Pilot/MPX/Output) does not exceed 5 Vpp.
 Disconnecting of the LCD backlight
Saves about 50 % of energy. The LCD is still well readable in daily or artificial lighting.
The LCD backlight connector (marked as
J19 on the main board) is accessible after opening the case using the four screws at the
bottom side of the cover.
The deviation range of the FM carrier caused by RDS/RBDS is 1.0 to 7.5 kHz .
The deviation range of the FM carrier caused by stereo pilot tone is 6.0 to 7.5 kHz .
The overall peak frequency deviation shall not exceed 75 kHz .