Atten AT6010 Kullanıcı Kılavuzu - Sayfa 7
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Due to the frequency conversion principle,a
spectral line is visible at 0Hz. It is called
If-feedthrough. The line appears when the 1st
LO frequency passes the If amplifiers and
filters. The level of this spectral line is
different in each instrument. A deviation from
the full screen does not indicate a
malfunctioning instrument.
Control Elements
The front view picture of the instrument (see
last page) contains numbers referred to below.
(1) Screen
(CRT)
(2) Focus
Beam sharpness adjustment.
(3) Intens
Beam intensity adjustment.
(4) Power
(Power ON and OFF)
If power is switched to ON position ,a beam
will be visible on the screen after
approximately.
(5) Ref level
(-27 to +13dB)
The Input Attenuator consists of four 10dB
attenuators, reducing the signal height before
nter-ing the 1st mixer. Each attenuator is
active if the push button is depressed. The
correlation of selected attenuation, reference
level, and baseline level (noise level) is
according to the following listing:
Attenuation Reference level
Base line
0dB
27dBm
10mV
107dBm
10dB
17dBm 31.6mV
97dBm
20dB
7dBm
0.1V
87dBm
30dB
3dBm
316mV
77dBm
40dB
13dBm
1V
67dBm
The reference level is represented by the
upper horizontal graticule line. The lowest
horizontal graticule line indicates the baseline.
The vertical graticule is subdivided in 10dB
steps. As previously pointed out, the
maximum permissible input voltages may not
be exceede3d. This is extremely important
because it is possible that the Spectrum
Analyzer will only show a partial spectrum of
currently applied signals. Consequently, input
signals might be applied with excessive levels
outside the displayed frequency range leading
to the destruction of the input attenuator and/
or the 1st mixing stage. Also refer to INPUT.
The highest attenuation (4*10dB) and the
highest usable frequency range (scanwidth
setting 50MHz/DIV.) should be selected prior
to any spectral to the AT6010/AT6011 input.
This permits the detection of any spectral lines
which are within the maximum measurable
and displayable frequency range if the center
frequency is set to 500MHz. If the baseline
tends to move upwards when the attenuation
is decreased, it may indicate spectral lines
outside the maximum displayable frequency
range (i.e.1200MHz) with excessive amplitude.
(6) TR
(Trace Rotation)
In spite of Mumetal-shielding of the CRT,
effects of the earth's magnetic field on
horizontal trace position cannot be completely
avoided. A potentiometer accessible through
an opening can be used for correction. Slight
pincushion distortion is unavoidable and
cannot be corrected.
(7) Display
Center Frequency / Ref level
(attenuator) / sweep span
(8) Center frequency
Coarse/Fine
Both rotary knobs are used for center
frequency setting. The center frequency
is displayed at the horizontal center of the
screen.
(9) Input 50 Ohm N connector
(10) Sweep span
1MHz to 1GHz (1-2-5 step)
(11) Video filter
The video filter may be used to reduce noise
on the screen. It enables small level spectral
lines to become visible which normally would
be within or just above the medium noise
level. The filter bandwidth is 4kHz.
(12) Bandwidth
Selects between 400kHz and 20kHz IF
bandwidth. If a bandwidth of 20kHz is
selected, the noise level decreases and the
selectivity is improved. Spectral lines
which are relatively close together can be
distinguished. As the small signal
transient response requires a longer time this
causes incorrect amplitude values if the
scanwidth is set at too wide a frequency
span.
(13) Y-Position
Control for adjusting the vertical beam
position.
(14) Phone
(3.5mm earphone connector)
An earphone or loudspeaker with an
impedance
16
can be connected to this
output. When tuning the Spectrum Analyzer to
a spectral line possibly available audio signals
can be detected. The signal is provided by an
AM-Demodulator in the IF-section. It
demodulates any available AM-Signal an
provides as well one-side FM-Demodulation.
The output is short circuit proof.
(15) Volume
Volume setting for earphone output.
(16) Probe power
The output provides a +6Vdc voltage for the
operation of an AZ530 near field sniffer probe.
It is only provided for this purpose and
requires a special cable which is shipped along
with the AZ530 probe set.
(17) Tracking generator
(AT6011 only )
(18) Attenuator
(AT6011 only)
0 to -40dB (4*10 step)
(19) Output level
(AT6011 only)
0 to -10dB
(20) Output Info
(AT6011 only)
FREQENCY: 1 to 1050MHz
AMPLITUDE: 0 to -50dBm
Output 50 Ohm N connector
Vertical Calibration
Prior to calibration, ensure that all input
attenuators (14) are released. The AT6010/
AT6011 must be in operation for at least 60
minutes prior to calibration. Switch VIDEO
FILTER (11) to OFF position, set
BANDWIDTH (10) to 400kHz, and
SCANWIDTH (15) to 2MHz/div.
Connect RF signal of -27dBm
0.2dB
(10mV) to the spectrum analyzer input (13).
The frequency of this signal should be
between 2MHz and 250MHz. Set the center
frequency to the signal frequency.
A:
A single spectral line (-27dBm) appears on
the screen. The spectral line maximum is now
adjusted with the Y-POS. control (12) and
placed at the top graticule line of the screen.
All input attenuators switches have to be
released.
The following adjustment is only necessary
for service purposes and if the check of this
setting shows deviations of the correct settings.
The Y-AMPL. Control is located on the
XY-PCB inside the instrument. In case any
adjustment of the vertical amplificationis
necessary, please refer to the service manual.
B:
Next, the generator signal must be
switched back and forth between -27dBm and
-77dBm, and the Y-AMPL. Control adjusted so
that the spectral line peak changes by 5
divisions in the vertical direction. If this results
in a change of the Y-position, the calibration
outlined under A and B have to be repeated
until an ideal adjustment is achieved. Finally,