User manual

Chapter 3 Signal Conditioning

Table 3-2 lists population options for passive signal conditioning

components.

Building Lowpass Filters

You can install simple, RC lowpass filters on any input channel of the

BNC-2090A. The filters are useful for accurate measurement and noise

rejection. By substituting resistance and capacitance values into

Equation 3-1, you can calculate a simple, one-pole RC filter to have a

–3 dB cutoff frequency (f

(3-1)

The frequency response rolls off at a rate of –20 dB per decade of increase

thereafter. Figure 3-3 shows a Bode plot of the amplitude versus

normalized frequency.

Table 3-2. Signal Conditioning Component Population Options

Configuration Normal Attenuator

Lowpass

Filter

Highpass

Filter

AC Couple Termination

Single-

Ended

A Open Open Open Open Open Resistor

B Open Open Open Open Open Resistor

0 Ω Jumper Resistor Resistor Capacitor Capacitor 0 Ω Jumper

E Open Open Open Open Open Open

F Open Resistor Capacitor Resistor Open Open

G Open Resistor Capacitor Resistor Open Open

Differential A Open Open Open Open Open Resistor

B Open Open Open Open Open Resistor

0 Ω Jumper Resistor Resistor Capacitor Capacitor 0 Ω Jumper

E Open Resistor Capacitor Resistor Open Open

F Open Open Open Open Open Open

G Open Open Open Open Open Open

Factory-installed 0 Ω resistor.

2πRC()

-------------------=