SI4721 datasheet(16/68 Pages) SILABS

16 / 68 page

AN388

Rev. 0.2

2.3.5. RDS Persistence

RDS Sync is influenced by the signal quality and strength. Once the RDS is synchronized, the FM tuner has the

ability to maintain its synchronization even with high BLER and fading signal strength. This test measures the

ability to maintain RDS Sync in degrading signal condition.

1. Connect test equipment as shown in Figures 1, 2, or 3.

2. Configure the tuner in standard configuration.

3. Set RDS ON.

4. Configure generator #1:

a. Set carrier frequency = 98.1 MHz.

b. Set RF level = 15 uV (RDS sensitivity level).

c. Select stereo modulation.

Set FM Deviation = 22.5 kHz.

ii. Set L=R.

iii. Set Source = LFGEN.

iv. Set LFGEN frequency = 1 kHz.

v. Set Pre-emphasis = 75 µs.

vi. Set Pilot = ON.

vii. Set Pilot Deviation = 6.75 kHz.

viii.Set RDS = ON.

ix. Set RDS Deviation = 2 kHz.

x. Set RDS Data Set = 1.

xi. Set Traffic Announcement = OFF.

xii. Set Traffic Program = OFF.

d. Enable modulation.

e. Enable carrier.

5. Slowly decrease the RF level until green "RDS"display on the main window of the Si47xx GUI goes off.

6. Record the RF level and BLER after 22 seconds.

SI4721 Datasheet(PDF) 16 Page - Silicon Laboratories