SMART ANTENNA
DVB-T USB dongle
DVB-T USB dongle with RTL2832U and R820T
Panasonic semiconductor’s MN88472 DVB-T/C/T2
demodulator IC is a second-generation, low power device
optimized to meet the exacting performance requirements
of the DVB-T2 specification.
The MN88472 includes an advanced LDPC algorithm
with reliability information, P1 detection and ISI
cancellation.
Sensitivity performance in 256 QAM modes is
exceptional and enables robust reception in areas with
extremely low signal power.
Main elements of a DVB-T USB dongle based on the
RTL2832U
MN88472 DVB-T/C/T2 demodulator IC
RTL2832U ADC chip
R820T tuner
Great for many applications including
• general radio scanning, air traffic control, public
safety, ADS-B aircraft radar, marine AIS, ACARS,
trunked radio, P25/MotoTRBO digital voice,
POCSAG, weather balloons, APRS, NOAA APT/
Meteor M2 weather satellites, radio astronomy,
DAB, or as a low cost panadapter with a ham radio.
• Tunes from 500 kHz to 1.7 GHz with up to 3.2 MHz
(2.4 MHz stable) of ( HF works in direct sampling
mode).
• Perfect for use as a computer based radio scanner
with free software like SDR#, HDSDR, SDR-Radio,
GQRX or SDR Touch on Android.
• Works on Windows, OSX, Linux, Android and
Computers like The Raspberry Pi.
• This RTLSDR model has several improvements over other
brands.
• It uses the improved R820T2 tuner, a 1PPM TCXO, better
components, a redesigned lower noise PCB, cooling
improvements, extra ESD protection and an SMA F
connector.
• It also has a software activatable bias- Tee for powering
LNA's and active antennas.
USB Tuner Receiver Aluminum Shell RTL-
SDR RTL2832U R820T2 100KHz-1.7GHz
USB Tuner Receiver Aluminum Shell RTL-SDR
RTL2832U, R820T2 100KHz-1.7GHz Features:
• Portable size, lightweight and compact.
• Fully assembled and ready to use
• using RTL2832U+R820T2 chip set.
• Covers all HF amateur bands, VHF & UHF bands from
24-1766MHz.
• R820T2 tuner has slightly better sensitivity than the
R820T and also works better at frequencies around 1.5
GHz. 100% compatible with software for the older R820T.
• Receiver modes: AM, NFM, FM, DSB, USB, LSB and
CW.
• Up to 3.2 M sample rate. (2.8 MHz stable)
• HF Shortwave Q branch is direct sampling.
• SMA golden antenna connectors. It is also more
practical and has lower insertion losses.
• Independent antenna inputs for Shortwave and VHF.
• USB computer connection (mini USB) is powered by
common USB.
• Operating frequency is from 100KHz to 1766MHz.
RTL2832U R820T2 Tuner
RTL2832U is a Coded
Orthogonal Frequency-
Division Multiplexing
(COFDM) demodulator IC
• The R820T2 is a silicon tuner integrated circuit
(IC) used in digital television applications.
• It has an ultra low power consumption of less than
178mA and operates on 3.3V.
• This tuner IC operates in conjunction with the
RTL2832U demodulator.
RTL2832U
• The RTL2832U is a Coded Orthogonal
Frequency-Division Multiplexing (COFDM)
demodulator IC manufactured by Realtek
Corporation.
• This IC receives intermediate frequency (IF)
signal from the R820T2 silicon tuner. It also
provides USB 2.0 connectivity to a computer.
• The IF operates on 36.125 MHz, 4.57 MHz,
and Zero-IF output. The crystal frequency is
usually 28.8 MHz.
• The SDR driver software allows operating the
tuner over a wide frequency range, and there
are drivers available for Windows and Linux.
voltage regulator
• Here is a voltage
regulator.
• These usually heat up a
lot.
Atmel flash memory chip
• This is an Atmel flash
memory chip to hold
the firmware.
RTL-SDR (Software Defined
Radio) with Dipole Antenna Kit
With this kit we can receive
frequencies from 500 kHz up
to 1.75 GHz
This device can be used in
• general radio scanning
• air traffic control
• public safety radio
• weather satellites
• radio astronomy
• meteor scatter
monitoring etc.
Dipole components
HUMAN HEARING SYSTEM
AN ANALOGY FOR SMART ANTENNA
DEFINITION
• A smart antenna system combines multiple antenna
elements with a signal processing capability to
optimize its radiation and/or reception pattern
automatically in response to the signal environment.
• Beam the radio signal directly at a user to follow the
user as they move.
Generalized Classification
TYPES OF SMART ANTENNA
• Switched lobe or switched beam:
Simplest technique
Basic switching function between separate directive
antennas or predefined beams of an array
The setting that gives the best performance, usually in
terms of received power, is chosen
Dynamically phased array:
Generalization of the switched lobe concept
Includes a direction of arrival (DoA) algorithm for
the signal received from the user
Continuous tracking can be achieved
Adaptive array:
DoA to determine the direction towards interferers is added
Radiation pattern can then be adjusted to null out the
interferers
Maximize the signal to interference ratio by special
algorithms & space diversity techniques (receive multipath
signals & combine)
How can an antenna be made more
intelligent..?
I. Modifying the physical design by adding more elements
II. Antenna system can shift the signals before transmission
at each of the successive elements for a composite effect
• Controlling signal phases
• A DSP weighting scheme
This basic hardware and software concept is known as
the ‘phased array antenna’
Types of D/A Converters
• We will consider two types of D/A:
o the binary weighted resistor network
o the R-2R ladder network.
The binary weighted resistor network
• Comprises of a register and resistor network
• Output of each bit of the register will be low (0V) or high (5V)
• Input resistance is inversely proportional to the binary weight
of each digit.
R I1 Rf
MSB
2R I2 If
4-bit register
4R I3 -
S I
LSB 8R I4 +
Vo
Vo I f R f ( I1 I 2 I 3 I 4 ) R f
DAC
where Vref is the Reference Voltage
of the circuit. Assuming the value
of Vref as 5 V, the Analog Output
Voltages corresponding to the
Digital Input Codes is shown in
Table.
D/A Example
In the previous D/A, calculate the output voltage for an input code
word 0110 if a logic 1 is 5V and a logic 0 is 0V, and
R = Rf = 1k.
Answer:
• I1 = I4 = 0
• I2 = 5V / 2R = 5 / 2KΩ = 2.5 mA
• I3 = 5V / 4R = 5 / 4KΩ = 1.25 mA
Vo = -If Rf
= -(I4 + I3+ I2+ I1)Rf
= -(2.5+1.25) x 1000
= -3.75 V
The binary weighted resistor network
• Very difficult to manufacture very accurate resistors
over this range.
• Seldom used for digital numbers having more than
6 bits.
The R-2R Ladder Resistor
• Network
Only two resistance values R and 2R are used.
• The principle of the network is based on Kirchhoff's current rule.
• Note that the network of resistors to the right of each node has an
equivalent resistance of 2R.
I I/2 R I/4 R I/8
Bit Current
2 I/2
1 I/4
2R 2R 2R 2R
0 I/8
I1=I/2 I2=I/4 I3=I/8
bit 2 bit 1 bit 0
The R-2R Ladder Resistor
Network
The state of the
bits is used to
switch a voltage
source
I I I
Vo R f b2 b1 b0
2 4 8
Successive-Approximation ADC
