BRUEL & KJAER 2006 User Manual

1t should be noted that for a high degree of modulation ( 70-80 % (kHz)) the
Recorder will record a modulation degree 2-5 % (kHz) too low owing to the
nonlinearity of the meter detector. This has been compensated for in the
meter circuit of the Heterodyne Voltmeter so that the meter indicates the
correct degree of modulation.
Fig. 4.16 shows the modulation frequency response of a signal generator
modulated with a Beat Frequency Oscillator Type 1022. By connecting the
BFO mechanically to the Level Recorder via a flexible shaft (UB 0041) and
using frequency calibrated paper (QP 1123, QP 0123, QP 0423) it can be
recorded automatically. Fig. 4.17 shows the measuring arrangement.
With regard to synchronizing the recording paper with the BFO reference
should be made to the instruction book of the BFO Type 1022 or of the Level
Recorder Type 2305.
Radiation from AM, FM and TV-Rt~ceivers.
The Heterodyne Voltmeter Type 2006 can also be used for measuring the
radiation from broadcast radio and television receivers. If more than just a
relative measurement is desired it is recommended, howeYer, to follow the
methods of measurement described in Publication 106 (1959) from the Inter-
national Electro technical Commission II .E.C.).
The Heterodyne Voltmeter Type 2006 Used as a Field-Strength Meter.
The Heterodyne Voltmeter Type 2006 may be used as a field-strength meter if
it is calibrated with an antenna in a known electrical field and the frequency
of the field to be measured is known. A frame antenna should be used for
the lower frequencies and although it may also be used for the higher fre-
quencies, i.e. for frequencies higher than about 50 MHz, it is just as con-
venient then to use a dipole-antenna. When calibrating the antenna should be
placed about four metres above ground.
If calibration is not possible a dipole antenna made of _ two telescopic.
antennas mounted together can be used for the frequency range from about
A.
50 MHz to 230 MHz, and should be adjusted to be 2 long (Fig. 4.18).
Connect the antenna to the Heterodyne Voltmeter Type 200() after haYing
calibrated the instrument as described in section 3.
The connection should be made by connecting a resistor of 75 Q across
the end of the antenna cable (matched) and then measure the voltage across
this resistor by means of the probe. Tune to the signal frequency with FRE-
QUENCY RANGE switch and TUNING knob. Turn antenna to maximum
response.
Find the correction factor, K(f), corresponding to the measuring frequency
(Fig. 4.18). The electrical field-strength is then found from:
E = K(f) X V volt/meter.
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BRUEL & KJAER 2006 Specifications

General

Brand	BRUEL & KJAER
Model	2006
Category	Measuring Instruments
Language	English