Philips CEM5000/00, Service Manual

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5.11 AC-Coupling
In some applications additional signal manipulations are desired, such as additional band equalizations.
For this purpose, an AC-Coupling can be placed before the loudness attenuator or speaker-attenuators,
which can be activated or internally shorted by I
2
C-Bus. In short condition, the input-signal of the speaker-
attenuator is available at the AC-Outputs. The input-impedance of this AC-Inputs is 50k
Ω
.
Figure 22. Diagram of AC coupling
5.12 DSO Applications
For DSO applications, DSO filter is available for additional processing after the speaker control. It is a 2nd
order Butterworth highpass filter with selectable flat mode. Figure 23 shows the diagram of the DSO that
includes an external RC network.
Figure 23. DSO diagram
To Output
ACINL
ACINR
ACOUTR ACOUTL
From Input MUX
Filters
InGain
Speakers
ACIN
/FILO
SE3IN
/AC2IN
ACOUT
/AC2OUT
External RC network
To
output
Gain Control
From speaker