29-08-2014, 12:31 PM
Simulation and Implementation of a BPSK Modulator on FPGA Seminar Report
[attachment=67317]
Abstract
The paper presents the simulation of a BPSK
Modulator using Matlab/ Simulink environment and System
Generator, a tool from Xilinx used for FPGA design as well
as the implementation of the modulator on a Spartan 3E
Starter Kit board. The modulator algorithm has been
implemented on FPGA using the VHDL language on Xilinx
ISE 12.3. The modulated signal obtained from simulations
was compared with the signal obtained after
implementation.
INTRODUCTION
The BPSK (Binary Phase Shift Keying) is one of the
three basic binary modulation techniques. It has as a result
only two phases of the carrier, at the same frequency, but
separated by 180º. The general form for the BPSK signals
are according to (1), where cf is the frequency of the
carrier.
¯
®
+=
−= =
c T
c T
i tfAts if
tfAts if ts
1),2sin()(
0),2sin()( )( 2
1
π
π
(1)
If “1” was transmitted, the modulated signal remained the
same as the carrier, with 0º initial phase, but if “0” was
transmitted, the modulated signal would change with 180º,
like shown in fig. 1.
The aim of the paper is to generate BPSK modulation
which is a popular modulation technique used in
communication industry, thus its symbol error
performance and bandwidth efficiencyThe paper is organized into 6 sections. Introduction
which represents section 1 describes the basics of the
BPSK modulation. In section 2, we offer information
about the hardware and software tools used. In section 3,
different implementations of the BPSK modulator in
Simulink and System Generator are presented. Section 4 is
dedicated to the implementation of the modulator on the
Spartan 3E Starter Kit board and section 5 to results. The
final section, 6, presents conclusions and future work.
BPSK Modulator in System Generator
System Generator is a digital signal processing design
tool from Xilinx, based on the Simulink environment
used for FPGA design. Designs are made in the Simulink
environment using a Xilinx specific blockset. All
implementation steps, including synthesis, place and
route are automatically performed to generate an FPGA
programming file [9].
Fig. 6 and fig. 8 illustrate an implementation of a
BPSK Modulator using System Generator tools in
Simulink
PSK MODULATOR ON SPARTAN 3E STARTER KIT BOARD
The BPSK Modulator that we implemented on the
Spartan 3E Starter Kit board has, as a model, the third
implementation in System Generator. The carrier is
generated internal, but in a ROM and that is the reason of
which the sinus signal is represented discontinuous, by
instantaneous samples of 16 different values [10], [11],
[12]. The only thing that is different is that we used a
switch that replaced the mux1 block. The switch behaves
as a random sequence of bits which introduces either “1”
or “0” depending on its position.
Fig. 12 represents the test bench lab used in
implementing the BPSK Modulator on the Spartan 3E
Starter Kit Board.
As explained in fig.2, the experimental setup consists of
a computer, a monitor, an oscilloscope, a pulse generator
and the Spartan 3E board.
The ISE Web Pack runs on the computer and it
programs the Spartan 3E board. The pulse generator
generates the signal from fig.13 and it is measured with a
LeCroy Wavesurfer Oscilloscope. The pulses are than fed
to an entry of a connector on the board like illustrates in
fig.14. Depending on the position of a slide switch
(fig.14), the modulating signal is acquired either external,
from the pulse generator or internal, from the LFSR.
Opposite to System Generator, the switch can be
represented or can be configured in VHDL language. The
modulated signal obtained is routed to the VGA port of
the board, in order to be seen on the monitor
RESULTS
After implementing the BPSK Modulator on the
Spartan 3E Starter Kit board, the signals were routed to a
monitor. The BPSK modulation can be seen in fig.15 and
16. If the input data is “1”, the transmitted signal to the
monitor is unchanged and has a green border on the right
of the figure, but if the input data is “0”, the transmitted
signal is yielded with 180º phase shift and has a red border
on the right of the figure.
Fig.17 represents the design summary which represents
the utilization of flip-flops, LUTs, slices used from the
capabilities of the FPGA from the Spartan 3E board.
CONCLUSIONS AND FUTURE WORK
We proposed two implementations of the BPSK
Modulator in the Matlab/Simulink environment, the first
with simple blocks and the second, with a block in which
we wrote Matlab code. Then, we made a proposal of three
implementations of a BPSK modulator in System
Generator. In the first, the three signals: the carrier, the
modulating and the modulated signals where generated
external. In the second scheme, the carrier is generated
external, and the modulating signal is generated internal
by a LFSR. And in the third scheme, all three signals were
generated internal with the exception of the modulating
signal which can be obtained either internal by the LFSR,
or external by the pulse generatorIn the second part of the paper, we implemented the
BPSK modulator on the Spartan 3E Starter Kit based on
the third proposal of the modulator made in System
[attachment=67317]
Abstract
The paper presents the simulation of a BPSK
Modulator using Matlab/ Simulink environment and System
Generator, a tool from Xilinx used for FPGA design as well
as the implementation of the modulator on a Spartan 3E
Starter Kit board. The modulator algorithm has been
implemented on FPGA using the VHDL language on Xilinx
ISE 12.3. The modulated signal obtained from simulations
was compared with the signal obtained after
implementation.
INTRODUCTION
The BPSK (Binary Phase Shift Keying) is one of the
three basic binary modulation techniques. It has as a result
only two phases of the carrier, at the same frequency, but
separated by 180º. The general form for the BPSK signals
are according to (1), where cf is the frequency of the
carrier.
¯
®
+=
−= =
c T
c T
i tfAts if
tfAts if ts
1),2sin()(
0),2sin()( )( 2
1
π
π
(1)
If “1” was transmitted, the modulated signal remained the
same as the carrier, with 0º initial phase, but if “0” was
transmitted, the modulated signal would change with 180º,
like shown in fig. 1.
The aim of the paper is to generate BPSK modulation
which is a popular modulation technique used in
communication industry, thus its symbol error
performance and bandwidth efficiencyThe paper is organized into 6 sections. Introduction
which represents section 1 describes the basics of the
BPSK modulation. In section 2, we offer information
about the hardware and software tools used. In section 3,
different implementations of the BPSK modulator in
Simulink and System Generator are presented. Section 4 is
dedicated to the implementation of the modulator on the
Spartan 3E Starter Kit board and section 5 to results. The
final section, 6, presents conclusions and future work.
BPSK Modulator in System Generator
System Generator is a digital signal processing design
tool from Xilinx, based on the Simulink environment
used for FPGA design. Designs are made in the Simulink
environment using a Xilinx specific blockset. All
implementation steps, including synthesis, place and
route are automatically performed to generate an FPGA
programming file [9].
Fig. 6 and fig. 8 illustrate an implementation of a
BPSK Modulator using System Generator tools in
Simulink
PSK MODULATOR ON SPARTAN 3E STARTER KIT BOARD
The BPSK Modulator that we implemented on the
Spartan 3E Starter Kit board has, as a model, the third
implementation in System Generator. The carrier is
generated internal, but in a ROM and that is the reason of
which the sinus signal is represented discontinuous, by
instantaneous samples of 16 different values [10], [11],
[12]. The only thing that is different is that we used a
switch that replaced the mux1 block. The switch behaves
as a random sequence of bits which introduces either “1”
or “0” depending on its position.
Fig. 12 represents the test bench lab used in
implementing the BPSK Modulator on the Spartan 3E
Starter Kit Board.
As explained in fig.2, the experimental setup consists of
a computer, a monitor, an oscilloscope, a pulse generator
and the Spartan 3E board.
The ISE Web Pack runs on the computer and it
programs the Spartan 3E board. The pulse generator
generates the signal from fig.13 and it is measured with a
LeCroy Wavesurfer Oscilloscope. The pulses are than fed
to an entry of a connector on the board like illustrates in
fig.14. Depending on the position of a slide switch
(fig.14), the modulating signal is acquired either external,
from the pulse generator or internal, from the LFSR.
Opposite to System Generator, the switch can be
represented or can be configured in VHDL language. The
modulated signal obtained is routed to the VGA port of
the board, in order to be seen on the monitor
RESULTS
After implementing the BPSK Modulator on the
Spartan 3E Starter Kit board, the signals were routed to a
monitor. The BPSK modulation can be seen in fig.15 and
16. If the input data is “1”, the transmitted signal to the
monitor is unchanged and has a green border on the right
of the figure, but if the input data is “0”, the transmitted
signal is yielded with 180º phase shift and has a red border
on the right of the figure.
Fig.17 represents the design summary which represents
the utilization of flip-flops, LUTs, slices used from the
capabilities of the FPGA from the Spartan 3E board.
CONCLUSIONS AND FUTURE WORK
We proposed two implementations of the BPSK
Modulator in the Matlab/Simulink environment, the first
with simple blocks and the second, with a block in which
we wrote Matlab code. Then, we made a proposal of three
implementations of a BPSK modulator in System
Generator. In the first, the three signals: the carrier, the
modulating and the modulated signals where generated
external. In the second scheme, the carrier is generated
external, and the modulating signal is generated internal
by a LFSR. And in the third scheme, all three signals were
generated internal with the exception of the modulating
signal which can be obtained either internal by the LFSR,
or external by the pulse generatorIn the second part of the paper, we implemented the
BPSK modulator on the Spartan 3E Starter Kit based on
the third proposal of the modulator made in System