28524 Quad Conditioner with Balanced Current Excitation

28524 Quad-Channel
Frequency to Voltage Converter Modules

The 28524 Quad Frequency-to-Voltage Converter Module provides conditioning for pulse, rate and frequency transducers.

The 28524 gives a voltage output proportional to input frequency or rate for frequencies from 1 Hz to 50 kHz with inputs from 10 mV to 100 V. Distorted inputs such as signals with ringing, crossover or harmonic distortion are handled with programmable trigger threshold and trigger hold-off time.

The 28524 is a member of the 28000 family of signal conditioners.

The user may select a limited band of frequencies within the 50 kHz range by programming a low frequency, F_L, and a high frequency, F_H, for each channel. The user may also specify the output voltages corresponding to these frequencies by selecting a low voltage, V_L, and a high voltage, V_H. The same voltage settings are applied to all channels on a card.

The measured frequency is displayed in the GUI and is updated approximately every ten seconds. This read-back feature can be disabled.

Test inputs, along with the system test bus and monitor bus make the card ready to work with the 28000 Test Subsystem hardware and software to support Go/No-Go and factory acceptance tests.

28524 Frequency-to-Voltage Module Features

4 channels per card, up to 64 channels per system
Graphical User Interface (GUI) for system control
1 Hz to 50 kHz frequency range
Up to 100 V input
16-bit output voltage resolution
Test input

28524 Programmable Features

Input frequency range: F_L, F_H
Output voltage output range: V_L, V_H
Low frequency roll-off
Trigger threshold
Positive or negative trigger
Hold-off trigger time
Prescaler
Input range

Selectable Trigger Type

The selectable edge trigger allows the user to choose the positive (leading) or negative (trailing) signal edge. Selecting the edge with the sharper transition produces a more stable output.

Programmable Trigger Hold Off Period

The programmable trigger hold-off time prevents false triggering on signal edges which cross the trigger threshold voltage but are not representative of the actual input frequency. On each valid edge, the trigger circuit is disabled for a period of time to ignore the false edges. An input signal with ringing could cause false triggering.

Programmable Trigger Threshold

The programmable trigger threshold allows the user to adjust the trigger voltage up or down to avoid distorted portions of the input signal. A signal with crossover distortion could cause false triggering.