Transcript Coding digital signals Boolean algebra, Boolean functions

Automation in electronics and telecommunication
Dr inż. Zdzisław Pólkowski
Badea George-Cosmin
http://www.momac.de/pop_el.html
Contents
1.
2.
3.
4.
5.
6.
7.
8.
9.
Automatic control system ;
Classification SRA;
Synthesis of controllers P, PI, PD, PID continue;
The design dead-beat controllers;
The design regulators Dahlin;
Designing regulators with allocation poles method;
Automatic control for amplification and frequency;
Control power supply in switching;
Sources
Automatic control system
Automatic control system
• SRA- Automatic system control;
• The automatic control system is then automatically resize the output
control and closed loop are made so that in the steady:
EP- prescribing element
EC- comparison element
R- automatic regulator
E- Execution element
M- measuring element
http://www.electrokoles.home.ro/auto%20web/05_Cap02-95.pdf
Classification SRA
Classification SRA
1. After character aprioric information on IT:
a) SRA with complete pre-requisite information:
• IT features are practically invariable in time.
b) SRA pre-requisite with incomplete information:
• These characteristics change in a manner not known before.
2. After dependencies- steady state- between
input and output sizes of components:
a) SRA linear:
•
When dependencies are linear.
b) SRA nonlinear:
•
When at least one of dependent is non-linear.
https://prezi.com/ekcw65td8bnq/clasificarea-sra/
Classification SRA
3. After character signal processing:
a) SRA continue :
•
When the all sizes involved are continuous in time.
b) SRA discrete:
•
When the least one of size has a discreet vibration in time.
4. After appearance time variation of input size:
a)
•
Automatic control systems:
If the input size is constant.
b)
•
Software systems:
If the size varies input is according to a particular program.
c)
•
Tracking systems:
If input size varies randomly in time.
https://prezi.com/ekcw65td8bnq/clasificarea-sra/
Classification SRA
5. By number of main loops:
a) A main loop systems;
b) Systems with several main loops or control systems.
6. Need for speed IT response to a signal being
input:
a)
•
SRA for fast processes:
IT’s time constans do not exceed 10.
b)
•
SRA for slow processes:
When IT have the time constants large and often have a dead time.
https://prezi.com/ekcw65td8bnq/clasificarea-sra/
Synthesis of controllers P, PI, PD,
PID continue
Synthesis of controllers P, PI, PD, PID continue
• In terms of automatic regulators continue constructive relies on the use
of electronic amplifiers correction circuit provided input and feedback.
Making laws by regulatory adjustment will depend on these two elements:
amplifiers used and circuits correction.
• At continue regulators, in functional terms, input and output sizes are
type continuously being made continuously addiction
. Linear
regulators performs a linear dependence between
and
. Linear
regulators types are: P, PI, PD, PID.
http://www.shiva.pub.ro/PDF/TRA/slide_curs9_TRA.pdf
Synthesis of controllers P, PI, PD, PID continue
1. Regulator with proportional action
•In this regulator, between the size of the input
it establishes a relationship of proportionality:
amplification factor of the controller.
P
and the command
; where is the
• If areas of input-output variation differs, the proportionality is given by
the relation:
http://www.shiva.pub.ro/PDF/TRA/slide_curs9_TRA.pdf
Synthesis of controllers P, PI, PD, PID continue
2. Regulator with proportional-integral action PI
•
This type of controller is a combination of a proportional regulator and
one full. PI control law controller contains a term that is proportional
action and a term P ensure integrator effect:
• The first form is the law regulating the type made by most industrial PI
controllers:
http://www.shiva.pub.ro/PDF/TRA/slide_curs9_TRA.pdf
Synthesis of controllers P, PI, PD, PID continue
3.Regulator with action proportional–derivative PD
• Such a regulator introduces a proportional component, similar to that of
the PI controller and a derivative component D introducing a
proportionality between the last component output size and the drift of
input sizes, . PD control law is expressed by:
• By using a PD controller is reduced during the transitional arrangements:
http://www.shiva.pub.ro/PDF/TRA/slide_curs9_TRA.pdf
Synthesis of controllers P, PI, PD, PID continue
4. Regulator proportional integral-derivative action
PID
• PID controllers are some of the most complex industrial regulators,
providing superior control performance. They capture the effects of
proportional P, integral I and derivative D above, the law regulating:
http://www.shiva.pub.ro/PDF/TRA/slide_curs9_TRA.pdf
The design dead-beat controllers
The design dead-beat controllers
• The dead-beat controller aims for the best response possible to a set
point change. Qualitatively, this means that following a set-point change,
and after a time period equal to the system time-delay, the output should
be at set-point and remain there. This requirement is formulated as:
• Where k is the system delay, expressed as an integer multiple of the
sampling interval Ts.
• The system delay has to be at least one, because the system delay
will include the unit delay due to the use of the sampler. At any
particular sampling instant, the current state of the controlled output is
sampled while at the same time, a control signal is sent to the process.
• The dead-beat controller is therefore given by:
http://lorien.ncl.ac.uk/ming/digicont/control/digital3.htm
The design regulators Dahlin
The design regulators Dahlin
• Less exacting control can be achieved by making the closed loop
behave like a first order plus time-delay system with unit gain, instead of
following set point changes in the quickest way possible as in dead-beat
control. That is we let:
• This is the z-transform of
where will be set equal to the
delay of the process being controlled. is the time-constant of the
desired closed loop response and can be used as a tuning parameter to
vary the speed of response. Substituting this into the synthesis
Equation, we obtain the following controller:
• which is known as the Dahlin Controller.
http://lorien.ncl.ac.uk/ming/digicont/control/digital4.htm
Designing regulators with
allocation poles method
Designing regulators with allocation poles method
• This method leaves from the general relationship:
in
which SRA transfer function is second order, ie:
• SRA design usually starts by placing poles dominant
and
in the
left half-plane C in complex plan, which mainly determine performance
SRA, so that in case of failure to satisfy performance requirements to be
introduced additional poles and zeros.
• The usual processes for more than two time constants (ef ≥2) is
recommended for the position
, next model:
http://www.engineering.upm.ro/master-ie/mse/mat_did/elen089/curs/C_1_4.pdf
Automatic control for amplification
and frequency
Automatic control for amplification and frequency
1.a. Sensitivity Time Control (STC)
• In radar receivers, the wide variation in return signal amplitudes make
adjustment of the gain difficult. Circuits used to adjust amplifier gain
with time, during a single pulse repetition period, are called STC
circuits, or “swept gain attenuator”.
• Sensitivity time-control circuits apply a bias voltage that varies with time
to the IF amplifiers to control receiver gain. The Figure shows a typical
STC waveform. When the transmitter fires, the STC circuit decreases
the receiver gain to zero to prevent the amplification of any leakage
energy from the transmitted pulse.
http://www.radartutorial.eu/09.receivers/rx08.ro.html
Automatic control for amplification and frequency
1.b. Automatic Gain Control (AGC)
• Gain control is necessary to adjust the receiver sensitivity for the best
reception of signals of widely varying amplitudes. A complex form of
automatic gain control (AGC) or instantaneous automatic gain control (IAGC)
is used during normal operation.
• The simplest type of AGC adjusts the IF amplifier bias (and gain) according to
the average level of the received signal. With AGC, gain is controlled by the
largest received signals. When several radar signals are being received
simultaneously, the weakest signal may be of greatest interest. IAGC is used
more frequently because it adjusts receiver gain for each signal.
http://www.radartutorial.eu/09.receivers/rx08.ro.html
Automatic control for amplification and frequency
1. Methods for adjusting the amplification:
• The vast majority of radar receivers use different methods for adjusting
the amplification. These methods generally acts on the amplification of
one or more intermediate frequency amplification stages.
• The simplest method is the manual adjustment by the operator
amplification. Other methods involve the use of special circuits which
carry out an automatic gain control, depending on various factors.
• Classification:
a) STC- sensitivity time control
b) AGC- automatic gain control
c) Log amp- logaritmic amplifier
d) Dynamic Swept Gain
http://www.radartutorial.eu/09.receivers/rx08.ro.html
Automatic control for amplification and frequency
1.b. Logarithmic Amplifier
• The logarithmic amplifier is a nonsaturating amplifier that does not
ordinarily use any special gain-control circuits. The output voltage of
the logarithmic amplifier is a linear function of the input voltage for lowamplitude signals.
• It is a logarithmic function for high-amplitude signals. In other words,
the range of linear amplification does not end at a definite saturation
point, as is the case in normal IF amplifiers. Therefore, a large signal
does not saturate the logarithmic amplifier; rather, it merely reduces the
amplification of a simultaneously applied small signal.
• This sum produces an increase in the output even though the final
stage is saturated. Detector 3 causes the output to continue to increase
after the second stage saturates. The overall gain becomes less and
less as each stage saturates, but some degree of amplification is still
available. The proper choice of IF stage gains and saturation points
produces an approximately logarithmic response curve.
http://www.radartutorial.eu/09.receivers/rx08.ro.html
Automatic control for amplification and frequency
1.b. Dynamic Swept Gain
• Local clutter levels dictate the magnitude of swept gain and differing
requirements for swept gain are presented as the antenna rotates.
Modern systems dynamically measure clutter levels for a large number
of cells within the coverage area of the radar.
• These measurements are slowly adjusted to take account of changing
clutter levels and used to set the swept gain attenuator to an
appropriate level for the range azimuth cell currently being processed.
In most cases, the values used are a variation on the normal static law.
http://www.radartutorial.eu/09.receivers/rx08.ro.html
Automatic control for amplification and frequency
2. Automatic Frequency Control
• The radar receiver requires a limited tuning range to compensate for
transmitter and local oscillator frequency changes because of variations
in temperature and loading. Microwave radar receivers usually use
automatic frequency control (AFC) for this purpose.
• Classification:
a) AFC in radio receivers;
b) AFC in radar sets.
http://www.radartutorial.eu/09.receivers/rx11.ro.html
Automatic control for amplification and frequency
2.a. AFC in radio receivers
• AFC circuits are used in situations where you must accurately control
the frequency of an oscillator by some external signal. The AFC circuit
senses the difference between the actual oscillator frequency and the
frequency that is desired and produces a control voltage proportional to
the difference.
• A varicap is used to keep the IF stable. The varicap application here
produces an apparent reactance, which is included in the oscillator
frequency control circuitry. For example, let's assume the IF is 10,7
megahertz and the local oscillator (LO) is tracking below the incoming
frequency.
• This variant of AFC circuits are used in radio receivers, fm transmitters,
and frequency synthesizers to maintain frequency stability. It requires a
relatively constant amplitude of the (received) input-signal. For pulseradar sets this form isn't practicable therefore.
http://www.radartutorial.eu/09.receivers/rx11.ro.html
Automatic control for amplification and frequency
2.b. AFC in radar sets
• Automatic frequency control circuits in a non-coherent or pseudocoherent radar use two different but similar systems:
a) The transmitters frequency readjust the receiver;
b) The receivers frequency readjust the transmitter.
• The Local Oscillator is adapted to the actual line frequency in this wiring.
As a second variant the control circuit can control the transmitters
frequency instead of the LO frequency! In this case the transmitterfrequency would regulated to the more stable LO-frequency.
http://www.radartutorial.eu/09.receivers/rx11.ro.html
Sources
• http://www.electrokoles.home.ro/auto%20web/05_Cap02-95.pdf
• https://prezi.com/ekcw65td8bnq/clasificarea-sra/
• http://www.shiva.pub.ro/PDF/TRA/slide_curs9_TRA.pdf
• http://www.creeaza.com/tehnologie/electronica-electricitate/Studiu-decaz-privind-proiecta413.php
• http://lorien.ncl.ac.uk/ming/digicont/control/digital3.htm
• http://www.engineering.upm.ro/master-ie/mse/mat_did/ elen089/curs/
C_1_4.pdf
• http://www.radartutorial.eu/09.receivers/rx08.ro.html
• http://www.radartutorial.eu/09.receivers/rx11.ro.html
• http://www.academia.edu/8283915/Surse_de_alimentare_in_comutatie