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measurement mode or 36.125 MHz in DVB-T signal demodulation mode by the tuner (T) with frequency
double conversion.
The signal of the second IF by means of mixer (M) controlled by the local oscillator (LO) is converted into
the third IF, and further is filtered at 10.7 MHz frequency by the bandpass filter (BPF3), which defines the
receiver measurement filter bandwidth.
Logarithmic gain amplifier limiter (LGAL) performs logarithmation and signal detection.
Signal detector (SD) allows measuring of signal level by means of analog-to-digital converter (ADC). SD
uses peak detection for measuring analog channel level and average detection for measuring noise level
and digital channel power. The digital code of the input signal level logarithm is defined as real value and is
corrected in accordance with the calibration matrix of the control unit (CU) microcontroller.
In DVB-T signal demodulation mode the signal with the second IF, after bandpass filter (BPF1) filtering
comes to DVB-T demodulator (Dm), which performs demodulation and signal parameters measurement. The
control unit processes the measured results.
The control unit receives the commands from the user entered via keypad (K), processes the data,
displays them on the LCD, and also controls the operation with external PC.
The nonvolatile memory (NVRAM) stores the calibration coefficients set by the manufacturer, data log
pages, channel template, channel plans and service information.
The Power Unit (PU) generates the required voltages either from battery or from an external power
source.
2.5.3 Component arrangement
The IT-14 is implemented in plastic shockproof sectional housing that includes printed and three-
dimensional wiring. IT-14 dimensions are 193x94x53 mm.
The front panel of the Analyzer represents the tactile silicon keypad and a graphical display (Figure 1.1).
The front panel has a connector for PC connection and external power source connector (Figure 1.2). The
input 75-Ohm input "F"-male connector is located on the rear panel.
Perform external examination to make sure your IT-14 is free from any visible mechanical damage.
Upon receipt of the package, check the availability of the items contained in it against the list provided
(Section 2.3).
If the IT-14 has been kept in the environment other than the rated operating conditions, leave your
Analyzer in facilities with normal operating conditions at least for 2 hours prior to operation.
4.1
Controls and indicators
The location of controls, indicators and connectors is shown in Figure 1.1. These elements have the
following functions:
a) F1, F2, F3 functional keys enable the commands corresponding to icons shown on the screen of IT-
14;
b)
key allows you to return to the previous menu level;
c)
key enables auxiliary functions;
d)
,
, ◄ , and ► arrows allow you to edit the current operation mode;
e)
key allows you to choose an element from the list;
f)
key switches the power of IT-14 on/off;
g)
12V DC 1.2A connector is for connection to an external power source;
h) USB
connector is for connection to a computer;
i) «INPUT» connector is for signal input, "F"-male connector.
4.2
Preparation for measurement
3
PREPARATION FOR OPERATION
4
OPERATION PROCEDURE
8
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