AD9851 DDS SWEEP / RF Power Meter

Mini-Kits AD9851 DDS-VFO Kit

Complete AD9851 DDS-VFO Kit

 

Please Note: that all information including pictures on this web page are copyright to Mini-Kits and must not be used on any other web site, or reproduced in any publication.

DDS-SWEEP Description:

The Sweep version uses the AD9851 DDS VFO Kit with the optional SWEEP Ver2.0 software to produce a simple sweep generator and RF power meter function using the optional RF Power Head Kits. Most of the functionality is dependant on the standard software that Mini-Kits supplies with the Kit.

The Software is designed to be used for a simple signal generator, but also has an in built sweep function with the addition of the Power Head Kit can also measure RF Power in dBm, Watts, Volts. Standard functions are Frequency Tuning, Step Size, Calibrate, Memory, Sweep Direction, Sweep Start Stop, Sweep speed, Fast Sweep, VFO/Sweep mode. The signal generator output can be used at the same time as reading RF from one of the Power Head Kits. So a filters 3dB BW can be measured by tuning the DDS generator by hand looking for the -3dB points of the filter. The Sweep function is only suitable for use with either a Spectrum Analyzer or Oscilloscope with a RF probe, as the sweep is too fast for the power head kits to read. Currently there is no trigger pulse available from the sweep generator for locking of an Oscilloscope.

The software does not allow for any display offset or Transceiver Radio functions, as it has been designed to make a useful piece of test equipment.

PLEASE NOTE: That this software does not have a trigger output pulse for locking either an Oscilloscope, or display when using the Sweep function. This would be a very useful addition, as many have asked for this to be added to the software.

If anyone is willing to modify the current Sweep software to produce a trigger output pulse, then Mini-Kits will supply the software files to you for free. The agreement is that it must be kept compatible with the DDS VFO hardware, and you must send Mini-Kits a copy of the software so that we can allow others to use it. We are suggesting that one of the spare pins either pin 15 or 16 on the PIC16F648A be used as an output.

Most functions of the Sweep software are similar to the DDS VFO software. Please refer to the DDS VFO Kit page for more information.

SWEEP Ver2.0 Software:

Although no problems have been found with the final Software version 2.0x since March 2010, Mini-Kits takes no responsibility for faults and minor glitches in the Software supplied with Kits.

Software Description.

Please refer to the SWEEP Ver2.0 Software documentation for more information.

All Software settings can be changed in the menu setting screens that are displayed on the LCD module. The keypad connected to the EME170 controller board along with the rotary encoder are used to change and memorize the menu settings into the PIC. No reprogramming of the PIC with a computer is required.

Below are the standard specifications for the software supplied by Mini-Kits. The SWEEP Ver2.0 Source code is available for download on the website for a nominal price to cover the development, and for future software updates.

  • Frequency range programmable from a minimum frequency of 1Hz, to a Maximum output frequency of 70MHz,( Using a 30MHz osc module and DDS x6 multiplier ).

  • Variable Rate Tuning and Adjustable Step Size 1Hz, 10Hz, 100Hz, 1kHz, 10kHz, 100kHz, 1MHz, 10MHz, 100MHz, 1GHz etc

  • Memorizes the last VFO or Memory frequency that showed on the LCD display on power up.

  • Programmed to use a low cost EC12E Mechanical Rotary Encoder.

  • Up to 11 Sweep Generator Memories can be programmed, ( Including start and finish frequency, and sweep rate ).

  • There are two Sweep modes Slow and fast, in each there are 10 sweep speeds. Please refer to the Readme document for more detailed information on the sweep width and speeds.

  • Calibration menu to program optional Power Head Kits.

  • Programmable for various Reference oscillator frequencies and DDS x1 or x6 Multiplier.

  • Programmable menu to set for when using an input attenuator or amplifier on the Power Head.

  • No trigger output pulse is available with this software to lock an oscilloscope to display the sweep display.

 

SWEEPGEN+ Software:

Please Note: This software does have bugs so please take this into account when using. Mini-Kits takes no responsibility for faults and minor glitches in this Software.

Software Description.

This software has been kindly provided by Colin Purton, and is based on the Mini-Kits SWEEP software but has a trigger output pulse available to lock an external display. Please refer to the Software documentation for more information.

This software is compatible with the Mini-Kits EME170 PIC controller and EME85 DDS Kits.

SWEEPGEN+ Beta_1 Software Download Provided by Colin Purton

Please email Mini-Kits with any improvements to this software so that we can add it to this webpage for others to use.

 

RF Power Meter Option:

1/ Optional RF Power Head Kits are available to suit the DDS-VFO when using the SWEEP Ver2.0 software. Kits are available for either a DC to 500MHz range, or 300MHz to 7GHz. The Sweep function allow the Power heads to display the RF power on the LCD display, and is useful for tuning filters using the DDS as a tunable signal generator. Please refer to the SWEEP Ver2.0 documentation for further information on how to use this option.

Kit Constructors Alert:

1/ Be very careful when connecting the EME167 board to the EME170 controller Kit. If you connect the ribbon cable on the IDC headers the wrong way around the DDS and or PIC controller could be damaged. Please refer to the DDS VFO Block diagram that shows from which direction the ribbon cable is connected between the boards. The Ribbon cable should always be kept very short and never be routed over the top of the EME167 DDS board. The IDC header key way should be positioned as per the block diagram to avoid mistakes. The Key way is normally used to indicate the identity of Pin 1 of the header, but this is not how we have fitted them to the board.

What DDS or Components are required:

APPLICATION: DDS SWEEP KIT SUITABLE AS A SIMPLE SWEEP GENERATOR AND RF POWER METER USING THE OPTIONAL RF POWER HEAD KITS.

Shown below is the complete DDS VFO Kit1 that is used by Mini-Kits for testing and development. The Kit we supply does not include the aluminium chassis, hardware or DC power connector, all other parts shown are included. BUY THIS PRODUCT

AD9851 DDS-VFO

Above shows the complete AD9851 DDS-VFO Kit

BUY THIS PRODUCT

What is included in the DDS-VFO Kit

  • 1 x EME167 KIT1 ( AD9851 DDS VFO Kit with a 30MHz oscillator module and 70MHz elliptic low pass filter
  • 1 x EME170 KIT ( AD9851 DDS Controller Kit )
  • 1 x LCD5 ( Blue/White 16x2 LCD Module with Backlight )
  • 1 x KEYPAD2 ( 16 Key Numeric 4x4 matrix )
  • 1 x 71 series 36mm diameter to suit EC12E
  • 1 x 2.54mm Header Connector Kit and 1 Metre ribbon cable
  • 1 x SMA33 ( SMA female PCB connector )
  • 1 x PIC16F648A ( Programmed with SWEEP Ver2.0 )
  • Enclosure Mounting:

    Front Panel of DDS

    Front panel view of a prototype DDS using SWEEP software in a Takachi Aluminium enclosure

    The picture shows the DDS VFO hardware with Sweep software mounted in a Takachi Aluminium enclosure. The enclosure is a 150x100x120mm size purchased from RS Components 401-8982. The front panel was cut out using a nibbling tool and filed with a very fine metal file.

    The LCD shows the reading when using the optional SWEEP software and an optional RF Power Head Kit.

    Kit Changes and Modifications

    DDS-VFO KIT

    1/ For any problems with this Kit, Please refer to the DDS-VFO and EME167 Kit Help web pages.

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