ymf795 Yamatake Corporation, ymf795 Datasheet - Page 33

• Manufacturer Part Number: ymf795
• Description: Apl-2 Automobile Sound Player-2
• Manufacturer: Yamatake Corporation

YMF795
■Volume level Adjustment in monophonic sound and 4-sound generation
The volume level outputted from DAC varies depending on the number of the pronunciation.
When one tone (*) is output from the FM sound source, output voltage amplitude from DAC becomes 0.4125 Vp-p.
When multiple sounds are pronounced at the same time, output voltage amplitude varies depending on phase of each
waveform, but when the waveforms with the same phase are overlapped, it becomes 0.825 Vp-p in 2-tone, 1.2375
Vp-p in 3-tone, and 1.65 Vp-p in 4-tone.
(*: This explanation is made on the assumption that volume adjustment (Total Level of Carrier) of one tone is 0 dB.)
An assumption of 300 mW output.
Assurance of volume level in monophonic sound.
FM
sound source
Output power of 300 mW can be obtained from the speaker when RL is 8 Ω and a voltage between SPOUT1 and
2 is 1.55 Vrms.
At this time, BTL output amplitude becomes 1.55×2×1.414=4.38 Vp-p, and EQ3 pin is 4.38/3.8=1.15 Vp-p.
“Gain adjustment in the EQ amplifier section” is recommended as a way to assure the volume level in
The Gain depends on the resistance ratio between R1 and R2, and Gain is equal to R2/R1.
The Gain of 3 times to 4 times is recommended.
monophonic sound.
(Gain with the speaker amplifier is +11.6 dB= 3.8 times.)
DAC
VREF
SP
VOL
-33-
HP
VOL
FM
VOL
+
BTL Driver
+11.6dB
-
EQ1
HPOUT
EQ2
EQ3
SPOUT1
SPOUT2
R1
R2
RL=8Ω