Peak Measurement; Alarm Function; Sound Demodulation Function - Chauvin Arnoux C.A 41 Bedienungsanleitung

4.4. PEAK MEASUREMENT

The PEAK function allows the user to take measurements with an acquisition speed of 1 ms for peak
measurements.
The 50 Hz filter for the rejection of low frequency fields is switched OFF. The C.A 41 becomes sensitive
to the power supplies of electrical equipment, to mains cable runs, ...
A first press on the PEAK button switcheds ON the function and the PEAK symbol appears on the display.
- The bargraph indicates the average value of highest peak values measured during 100 ms.
- The digital display indicates the average of the 16 peak values measured during 400 ms. A
second press on PEAK switches OFF rapid acquisition and the PEAK symbol goes out.
Note: When the RECORD and PEAK symbols are displayed, the peak values are recorded (MIN, MAX
and AVG) with a measurement constant of 1 ms.

4.5. ALARM FUNCTION

When the rotary switch is positioned on the V/m (AL) symbol, the alarm function is ON and the HI AL
symbol appears on the display.
All the measurements are compared to the threshold value preset by the user (see below). If the value
measured is greater than or equal to this threshold value displayed in inverse video on the bargraph,
then the buzzer is permanently ON (at F = 4 kHz) and a triangle appears on the display, on the right of
the HI AL symbol.
Adjusting the alarm threshold
The alarm threshold is preset at the factory: 3 V/m.
To modify the alarm threshold:
- with the instrument switched OFF, open the battery compartment on the back of the instrument
with a coin (tool release screw).
- the adjustment potentiometer is accessible via a hole located in the upper left corner of the
battery compartment.
- check that the battery is still correctly attached to the instrument.
- turn the rotary switch to the V/m or V/m (AL) position whist pressing the PEAK button (the
present threshold value is displayed).
- keep the PEAK button pressed and vary the value of the alarm threshold by turning the
potentiometer.
- once the value id displayed, leave the potentiometer in position and release the PEAK button.
- close the cover.

4.6. SOUND DEMODULATION FUNCTION

The demodulation function allows the amplitude modulation which may be present on the HF signal to
be heard on an internal loud speaker. This detection of modulation is limited to the audible frequencies
between 500 Hz and 5 kHz inclusive.
The best result is obtained for fields measured between 5 V/m and 30 V/m inclusive with a modulation
depth of 50% minimum. As a result of the filtering contants of the instrument, this function is only available
on PEAK mode.
This function is controlled by a switch coupled to a single turn potentiometer (4) of the instrument. The
potentiometer allows adjustment of the sound volume as a function of the field and the depth of modulation.
Note : The power consumed by the internal speaker greatly reduces the service life of the battery. Please
only use this function for real applications. We recommend switching OFF the demodulation function with
switch (4) as soon as it is no longer used.
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