WHAT
BITS DO I REQUIRE FOR MY APPLICATION?
The
first part is to discuss the specifications of the software so that
you can determine if any of the DDS kits are suitable for your application.
As of August 2009 only DDS circuit hardware
Applications 1 & 3 are available, see below.
WHAT
WILL THE DDS & SOFTWARE ALLOW YOU TO DO?
The
Software dd_synth_ver2.1 & the newer ver2.2 have the same functionality
& only the hardware has changed.
The Software is designed to be used for a simple signal generator,
but also has if you like, 2 VFO's for RX & TX display frequency
that can have the frequency display set differently from the actual
DDS output frequency. This is useful for receivers or transmitters
with an IF, ( Intermediate Frequency ). So yes it can be used on
a receiver that has an eg 9MHz IF by setting the display offset
by 9MHz. It is however not suggested that the DDS just be connected
to a radios mixer without a suitable bandpass filter on the output
of the DDS. DDS chips produce lots of outputs that although many
dB under the actual output frequency can still mix in a radios mixer,
& produce spurious output. The best way to use a DDS on a Radio
is to use a 1:1 Phase Locked Loop circuit & use a separate VCO
oscillator as the actual oscillator for the Radio & the DDS
for the PLL's reference.
BASIC
SOFTWARE SPECIFICATIONS
1/
Frequency range programmable from a minimum frequency of 1Hz, to
a Maximum output frequency of 60MHz, ( Using
a 30MHz osc module & DDS x6 multiplier ).
2/ TX /
RX Display readout can be offset by + or - 1Hz to 11GHz, (
Suitable for Repeater or IF Offsets ).
3/ No Band
Switching, or Mode switching available.
4/ Memorises
the last frequency on power up.
5/ Up to
22 Memory frequencies & settings can be programmed. (
Depends on what options have been programmed, eg RX only, RX/TX
use, or RX/TX & Repeater etc ).
6/ Programmed
to use a low cost Mechanical Rotary Encoder.
7/ Variable
Rate Tuning & Adjustable Step Size 1Hz, 10Hz, 100Hz, 1kHz, 10kHz,
100kHz, 1MHz, 10MHz, 100MHz, 1GHz etc
8/ Software
fine tuning of the Reference oscillator frequency.
9/ RIT
( Receive Incremental Tuning ) in RX mode only.
10/ Programmable
for various Reference oscillator frequencies & DDS x1 or x6
Multiplier.
Refer
to the dd_synth_ver2.1 Software Notes for more detailed information
& Use, Download Here
Refer
to the dd_synth_ver2.2 Software Notes for more detailed information
& Use, Download Here
APPLICATION
1
Only works
with dd_synth_ver2.1 Software. This hardware setup is not supported
in the new dd_synth_ver2.2 software after
( July 09 ). The
Minimum Component Requirement to make a DDS with an output frequency
from 0 to 60MHz. The 4 x Pushbuttons are for, Step Size, Calibrate,
Receiver Incremental Tuning, & Repeater. You don't have to use
all 4 functions, but Step Size & Calibrate will require switches.
1 x EME85
KIT ( Basic DDS Kit )
1 x EC12E
( Mechanical Rotary Encoder ) Requires a Knob
to suit a 6mm diameter Shaft
1 x KNOB2
71 Series 28mm diameter Knob & Cap to suit EC12E
1 x OSC3
100MHz, or OSC4 30MHz Oscillator Module
1 x 30MHz,
or 70MHz KIT ( Elliptic Low Pass Filler )
1 x LCD1,
3, or 5 ( 16x2 LCD Display Module )
4 x 1N4148
Diodes
4 x Switch5
Momentary Contact
1 x Metre
10 Way Ribbon Cable
To control
the DDS circuit you will have to build the control circuit yourself.
It is so simple to build something on a piece of veroboard,
that PC Boards are not available from Mini-Kits. You will
need to buy a few 1N4148 diodes & a few momentary pushbutton
switches if you don't have some. You might even decide to mount
the switches on the front panel of a project box. The minimum requirement
of switches is, the Step Size & Calibrate to make a simple signal
generator.
Download
Basic Ver1 Control Circuit Here
APPLICATION
2
Works with
either dd_synth_ver2.1 or 2.2 Software. This hardware setup is no
longer being sold after July 2009 & has been changed to the
Version 3 hardware.
The Minimum Component Requirement to make a DDS with an output frequency
from 0 to 60MHz, with advanced features like memories & direct
keypad entry. The EME129 Control Kit, ( No
Longer Available ) has 6 Pushbuttons, Step Size, Calibrate,
Memory, Receiver Incremental Tuning, Repeater, & one Spare position.
1 x EME85
KIT ( Basic DDS Kit )
1 x EME85
Header Connector Kit
1 x EC12E
( Mechanical Rotary Encoder )
1 x KNOB2
71 Series 28mm diameter Knob & Cap to suit EC12E
1 x OSC3
100MHz, or OSC4 30MHz Oscillator Module
1 x 30MHz,
or 70MHz KIT ( Elliptic Low Pass Filler )
1 x LCD1,
3, or 5 ( 16x2 LCD Display Module )
1 x EME129
( CONTROL BOARD2 KIT ) THIS KIT IS NO LONGER
AVAILABLE
1 x KEYPAD1
( 12 Key Numeric Keypad 3x4 matrix )
1 x SMA09
SMA Female PCB Socket
1 x PIC16F628DDS2.2
Programmed PIC Micro with dd_synth_ver2.2 software
1 x Metre
10 Way Ribbon Cable
To control
the DDS circuit it is recommended that you use the EME129 Control
Board Kit. If you try & build it yourself, it can be a bit complex
to wire up the 16 diodes & switches correctly. The EME129 Control
board circuit can be downloaded below.
Download
EME129 KIT Ver2 Control Circuit Here
The Application
2 hardware above is no longer being sold after July 2009 & I
recommend that you look at Application 3 below.
APPLICATION
3
After July
2009. Works with dd_synth_ver2.2 Software only. This hardware setup
is now the same as the Sweep Kit & uses the Version 3 hardware.
The Minimum Component
Requirement to make a DDS with an output frequency from 0 to 60MHz,
with advanced features like memories & direct keypad entry.
The complete DDS VFO KIts use the EME159 control Kit & 4x4 Keypad,
& no longer require separate switch buttons as in Version 2
above to set Step Size, Calibrate, Memory, Receiver Incremental
Tuning, Repeater, etc.
1 x EME85
KIT ( Basic DDS Kit )
1 x EME85
Header Connector Kit
1 x EC12E
( Mechanical Rotary Encoder )
1 x KNOB271
Series 28mm diameter Knob & Cap to suit EC12E
1 x OSC3
100MHz, or OSC4 30MHz Oscillator Module
1 x 30MHz,
or 70MHz KIT ( Elliptic Low Pass Filler )
1 x LCD1,
3, or 5 ( 16x2 LCD Display Module )
1 x EME159 ( CONTROL
BOARD3 KIT ) This Kit includes the EC12E
encoder, but it still requires a Knob to suit the EC12E 6mm diameter
Shaft
1 x EME159 Header
Connector Kit
1 x KEYPAD1
( 16 Key Numeric Keypad 4x4 matrix )
1 x SMA09
SMA Female PCB Socket
1 x PIC16F628DDS2.2
Programmed PIC Micro with dd_synth_ver2.2 software
1 x Metre
10 Way Ribbon Cable
To control
the EME85 DDS it is recommended that you use the EME159 Control
Board Kit as the interface to the 4x4 Keypad & LCD module. If
you try & build it yourself, it can be a bit complex to wire
it all up on vero board & make it work. The Version 3 Circuit
can be downloaded below.
Download
EME159 KIT Ver3 Control Circuit Here
If this
is the DDS Hardware that suits your application, then I would recommend
that you purchase the complete DDS VFO KIT1 or 2 from Mini-Kits
which includes all the above & a knob to suit the EC12E encoder.
Click Here
Refer
to the dd_synth_ver2.2 Software Notes for more detailed information
& Use, Download Here
Saturday
31st December 2011
