MAX275AEWP+ 其他数据使用手册 - Maxim Integrated（美信）

Figure 4. Noise pulse blanking.

The block diagram of the blanking circuit is Figure 5.

Figure 5. Noise-blanking block diagram.

From the basic concept of blanking in Figure 5, more elegance can be added. The input buffer may not

is on and AIN2 is off. We highpass or differentiate the noise pulse. The dual or window comparator

output will be active while the noise pulse exceeds 0.3V in either the positive or negative direction. The

XOR gated inverts the logic to the mux, thereby turning off the main path and switching on the DC

voltage. The RC delay also delays the main path long enough for the comparator path to change state. If

the RC delay degrades the signal bandwidth too much, an LC delay line can be substituted.

The input buffer of Figure 5 could use a MAX4209 instrument amplifier which has incredibly low offset

drift despite its high gain. Application note 4179, "Autozero Noise Filtering Improves Instrumentation

Amplifier Output," explains why.

The filter just before the ADC in Figure 5 can control signal bandwidth to meet Nyquist anti-aliasing,

reduce noise, or soften the residual blanking glitch. The following application notes will provide advice