LV2285VB_11 Datasheet, PDF (10/11 Pages) Sanyo Semicon Device – FM transmitter IC with Stereo Modulation, Auto Sleep Function

Usage note
LV2285VB
Stereo modulation
In generally, How to generate stereo modulating signals explain below figure 1. LV2285VB generate composite signal
like below figure 2. And it is possible to control sub signals at register [ST]. Pilot signal is controlled at register
[PILOT]
38kHz [ST]
Rch (24pin)
Lch (1pin)
19kHz [PILOT]
Figure 1
ATT [2:0]
Composite output (pin 7)
Main
(L+R)
PILOT
Sub
(L−R)
0
15 19 23
38
53
Frequency [kHz]
Figure 2
FM modulation
The LV2285VB have best performance of FM modulation at
±75kHzdev.
FM modulation level changes in proportion to composite
output level (pin 7)
In LV2285VB composed of recommended parts, Table 1 is
shown relationship that set ATT [2:0] value against audio
input signal level.
Please refer to Table 1 to obtain better audio quality.
Table 1
Audio input signal level V.S ATT[2:0] setting
Large attenuation
000 L , R input level = 780mVrms
001 L , R input level = 640mVrms
010 L , R input level = 425mVrms
011 L , R input level = 260mVrms
100 L , R input level = 190mVrms
101 L , R input level = 140mVrms
110 L , R input level = 110mVrms
Small attenuation
111 L , R input level = 80mVrms
No.A1494-10/11