CXA1878Q
(2) AMS OFF operation
When the input signal disappears, the capacitance connected to the AMS TC pin (Pin 37) is discharged,
causing the TC pin voltage to rise above the threshold value and turn AMS OFF.
(3) AMS gain setting method
The AMS gain (G1/G2 mode gain) adjustment can be determined by external resistances R1 and R2.
In addition, AMS gain is expressed by the following equations.
R1 + 100kΩ (internal resistance)
G1 = 20 log
G2 = 20 log
dB
dB
R1
R2 + 100kΩ (internal resistance)
R2
dB
[ 2]
[ 1]
G1 NOR (BS)
G2 FF (AMS)
[ 2]
[ 1]
Frequency
(4) AMS low frequency cut-off setting method
The AMS low frequency cut-off adjustment can be determined by external resistances R1 and R2 and
capacitances C1 and C2.
(5) Relationship between response time and sensitivity
The AMS ON time is determined by the width of the pulse obtained by applying the input signal to the
WINDOW comparator. The pulse emitted from the WINDOW comparator becomes extremely small near
the detection level, and some time is required for this pulse to be integrated by the external capacitance,
thus lengthening the response time.
Response times can be adjusted to approximately the same value by adjusting the AMS sensitivity with
resistances R1 and R2 to match the various ICs. Also, the AMS OFF time is determined by the external
time constant (R3, C3).
Notes on Operation
Temperature characteristics and accuracy of the recording equalizer amplifier
The temperature characteristics of the built-in monolithic filter and the filter cut-off frequency depend on the
27kΩ external resistance connected to the IREF pin (Pin 10). Also, the recording equalizer amplifier
frequency response depends on unevenness in the absolute, as well as relative values of the internal
capacitance. Furthermore, the high frequency response indicates a high element sensitivity at the filter
because the band-pass filter Q is high. Compared to low frequency, although the unevenness inherent in
the IC is more likely to occur, this occurs relatively, and not individually for channels 1 and 2.
– 30 –
SONY [ SONY CORPORATION ]
