TV Converter Box User's Manual

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3.2 Bipolar Input to Channel A0
Analog Interface
NOTE: Components marked NI are NOT INSTALLED.
Figure 1. Channel A0 Input Circuit
This configuration allows single-ended signals of ± 2.5 V (+5 Vpp) to be applied to either input of channel
A0 (J2 pin 1 or 3 referenced to pin 2). The input also can be applied to connector J4 (not shown) pins 2 or
4, referenced to analog ground.
By changing components and setting the appropriate jumper, it is possible to configure the input buffer to
accept bipolar input voltages. Table 1 is related to the schematic presented in Figure 1 and represents just
a few of the possible input configurations.
Table 1. Typical Analog Input Buffer Circuit Values
Input Voltage R3 R2 R1 R4 W2
R28 R25 R24 R29 W1
Refer to Figure 1 Default open 5k Ω 5k Ω 5 k Ω 1–2
0 – +5
0 – 2.5 5 k Ω 5 k Ω open 5 k Ω 2–3
– 2.5 – +2.5 20 k Ω 4 k Ω 20 k Ω 4 k Ω 2–3
– 5 – +5 20 k Ω 4 k Ω 10 k Ω 2 k Ω 2–3
– 10 – +10 20 k Ω 4 k Ω 5 k Ω 1 k Ω 2–3
SLAU189 – September 2006 ADS8364/65MEVM 3
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