CXA2509AQ View Datasheet(PDF) - Sony Semiconductor
Part Name
Description
Manufacturer
CXA2509AQ Datasheet PDF : 21 Pages
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CXA2509AQ
3. Playback equalizer amplifier
Gain (dB)
T1
G1
PB IN
FWD
RVS
SW1
AMP1
SW2
70µs
–6dB/oct
T2
PBREF
PBFB
R1
PBEQ
R4
C1
R3
R2
PBOUT
Fig. 3. Playback equalizer amplifier
block diagram
T3
f1
f2 f3 Frequency (Hz)
Fig. 4. Playback equalizer amplifier
frequency response
The CXA2509AQ achieves the frequency response of Fig.4 with the circuit configuration shown in Fig. 3.
Two systems (FORWARD and REVERSE) of playback head input are provided for each channel.
The FORWARD input pin is selected when DRSW (Pin 19) is Low; REVERSE is selected when DRSW is
High.
The playback equalizer amplifier frequency response can be set in two levels.
When TAPESW (Pin 18) is Low, SW2 shown in Fig. 3 is turned OFF; when TAPESW is High, SW2 is turned
ON.
The external resistance R1 should be adjusted to adjust the playback equalizer amplifier gain.
The playback equalizer amplifier frequency response is all determined by the external resistance and
capacitance, and it can be obtained with the following equation.
G (s) =
R1 + R2
R1
·
1 + {s · C1 · (R1 · R2 + R2 · Rx + Rx · R1) / (R1 + R2)}
1 + s · C1 · (R2 + Rx)
(s = jω)
Where, Rx = R3 when TAPESW pin = Low;
Rx = R3//R4 when TAPESW pin = High
Using the above equation, G1 in Fig. 3 and low-frequency time constant (T1) and high-frequency time
constants (T2 and T3) are as follows:
G1 = 20log
R1 + R2
R1
T1 = C1 · (R2 + Rx)
T2, T3 =
C1 · (R1 · R2 + R2 · Rx + Rx · R1)
R1 + R2
– 15 –
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