BU9253FS ROHM Co. Ltd., BU9253FS Datasheet - Page 13

• Manufacturer Part Number: BU9253FS
• Description: Karaoke/surround Digital Echo
• Manufacturer: ROHM Co. Ltd.

・
・
* The set values in this document are for reference only. In the actual set, characteristics may change according to board
IN
layout, wiring, types of parts used, and therefore, in actual use, carry out sufficient verification with the actual devices.
LPF and echo system gain
Clock oscillation
When the ratio of original signal and echo is changed, R5, R6, R9, R11 are also changed, and the characteristics of LPF
change too. Therefore, it is necessary to change all the constants of LPF. In the case, to precisely measure the ratio of
original signal and echo, remove R7, input signal around 500Hz without the influence of LPF from MIX IN, and compare
it with the output of DALPF OUT.
As for C,R, tolerance should be below 5%. Note: If measurement is made by attachment a probe oscilloscope it might
load the oscillator and reduce the oscillation frequency.
R5
R9
Fig.35 LPF and echo system gain
C5
C7
R6
R10
R4
R11
－
＋
C4
C8
OUT
13/16
Q generally about 0.7
Echo signal amplitude ratio
Q
Q
エコ－信号増幅率
fc
A
=
は一般的に
1
A
=
=
=
1
R
2
×
R
R
π
4
A
4
5
R
2
C
5
4
=
+
1
C
1
R
R
0.7
R
5
A
4
R
5
R
4
ぐらい
2
R
×
6
4
×
R
R
5
=
R
11
5
9
R
R
11
C
9
5
R
C
4
4
R
5