The present invention confirms and validates the operating parameter and
specification of Video Amplifier used for amplifying the signals and generation of
different logic in form of shaping the sign of presence of signal in different channel. In
addition to desired parameters, suppression of channel and background noise received
from the Photo diodes is accomplished through same electronics device under
checking.
BACKGROUND OF THE INVENTION
Electronics Modules plays crucial role in every industry. Specifically in aerospace
domain, it is desired to obtain critical functions of aerodynamics, flight controls,
processing of navigational and attack parameter and display of various modes through
dedicated Line replaceable Unit which have sub-assembly of specific electromechanical
& optical modules. Video Amplifier is one of these module meant for performing
frequency processing and amplification of signals received from IR photo diodes along
with channel & background noise & logical addition of signals of different channels.
The present invention is concerns with checking the functional &
operational behavior of a particular electronics module (video amplifier) in such an
environment which is suited for optoelectronics system of aircraft.
SUMMARY OF PRESENT INVENTION
In accordance with one aspect of present invention, using passive electronic
components and interconnects, a system is fabricated.
In accordance with second aspect of present invention, is a cost effective apparatus.
In accordance with another aspect of present invention, is simple & easy to repair and
maintain.
In accordance with another aspect of present invention, user friendly from operation
point of view.
In accordance with present check apparatus, this invention is portable, light in weight.
Annexure‐II
Video amplifier is very low noise high impedance with 1000 amplification factor
and high band width amplifier. For testing of high bandwidth range amplifier, Additive
White Gaussian Noise is mixed with input signal to simulate real time input of Video
amplifier at different frequency range and voltage level. White Gaussian noise is fed
from noise generator and input signal is fed from Signal generator. The present
invention mix these signals and gives mixed signal to input of video amplifier. Different
outputs of video amplifier are present of different point of panel. These output signals.
Panel is a combination of simple wire and passive component so it does not required
any biasing voltage. Calibration procedure of this panel is easy in form of continuity
checks and measuring of resistance at specific points.
BRIEF DESCRIPTION OF THE DRAWINGS
The features and advantages of the present invention will become more apparent and
descriptive in the description when considered together with figures/flow charts
presented:
Fig. 1 is a Front Panel of Check Apparatus
Fig. 2 is a Block Diagram of Check Apparatus
Annexure‐II
DETAILED DESCRIPTION
This apparatus generates mixture of real time analog signal with channel noise
which is achieved through variable resistance of 100K Ohms (max) & 5.6K Ohms
(max). These resistances are part of Op-Amp Adder circuit which was used in
preamplifier stage of video amplifier module. Mixed Signal was fed to Input terminal of
Video Amplifier which is used to setting reference technological signal through
potentiometers situated in test apparatus which can be verified at “Tech” point of test
apparatus.
One pre amplifier & three analog multiplier separated by RC differential circuits
are part of preliminary circuit of Video amplifier. Input signal from the output of IR diode
is driving force of input of first stage of amplifier, which is assembled on OP Amp circuit.
Amplification of signal is ensured by analog multipliers, which are separated by
differentiating circuits, combination of RC circuits.
Adjustment of amplification factor is achieved through by control signal Vin ARUS
from test apparatus. The analog multipliers perform the function of adjusting elements,
ensuring frequency response of amplifying path is ensured by active filter as well as by
differentiating RC circuits.
There is an amplifier-limiter on which noise voltage from output of multiplier is fed
which send limited output to RC filters. After filtering through RC filter for required
shaping, desired signal is to be entered to the input of threshold limiter. Amplification
adjustment signal from point of test apparatus and the signal from the output of second
stage filter are fed to threshold limiter. Amplification adjustment signal is achieved
through a simple circuit containing Voltage -15V & resister 37K Ohms & 10K Ohms.
Output signal of threshold limiter enters to the logical addition stage and amplifierlimiter.
The threshold voltage for matching device is generated through +15V and
variable resistances from test apparatus which is fed into input of amplifier-limiter. The
Annexure‐II
signal from amplifier-limiter shapes indication of presence of target in the form of logical
<< 0 >> at output of logic output amplifier.
Point wise signal description used in test apparatus is as below:
1. Noise: This is the noise input generally generated from a standard Noise
generator. It is basically Additive White Gaussian Noise up to frequency range up
to 600 KHz. This Noise is simulation of noise generated through randomness of
heat imparted on IR photo diode.
2. Signal: A 200Hz with pulse width of 400 μs is fed into signal point of test
apparatus. This pulse is generated through standard pulse generator.
3. Tech: This is technological output signal from video amplifier for setting
amplification factor.
4. Noise Output: With the help of limiter section as per requirement, it is the
threshold setting for technological output.
5. Analog Output: This is analog output used for further processing of target
intensity. This information is used to control position of diaphragm.
6. AC Signal: This is AC signal used for presence of target.
7. Logic Signal: Logic signal is generated internally in video amplifier with the help
of analog signal and it is used for calculation of target positional co-ordinate.
8. Supply Points: +15 V, -15 V, +10 V and Common (GND) used for various power
supply requirements of video amplifier module & its internal electronic
components.

WE CLAIMS:
1. The said check apparatus, comprising
- A non-conductive plate for fixing electronic components and interconnecting it using conductive wires,
- A panel for input/output,
- Respective looms and cables for connecting unit under test &
- Generic test devices
2. The system as per claim 1, using passive electronic components and interconnects, a cost effective apparatus is fabricated.
3. The system according to claim1, capable of testing video amplifier modules.
4. The check apparatus of claim 1, has increased reliability due to used for passive electronic components, consumes less power.
5. The system according to claim 1, is robust, light weight and is portable.
6. The system according to claim 1, is simple & easy to repair and maintain.
7. The system according to claim 1, is user friendly from operational point of view.
8. The system according to claim 1, has adjustable noise level provisions.
,TagSPECI:As per Annexure-II