This version is outdated by a newer approved version.
This version (14 Sep 2012 15:42) is a draft.
Approvals: 0/1
This version (14 Sep 2012 15:42) is a draft.Approvals: 0/1
This is an old revision of the document!
Table of Contents
~~under construction~~
AD9129-CBLTX-EBZ Cable Transmitter Evaluation Board Quick Start Guide
Getting Started with the AD9129 Cable Transmitter Evaluation Board and Software
What's in the Box
- AD9129-CBLTX-EBZ Evaluation Board
- Mini-USB Cable
- Evaluation Board CD
Recommended Equipment List
- +5Vdc, +8 Vdc Power Supply
- Data Pattern Generator Series 2 (DPG2)
- Spectrum Analyzer Ex: Agilent PXA or Rohde Schwarz FSU
Introduction
The AD9129-CBLTX-EBZ connects to a DPG2 to allow for quick evaluation of the AD9129, a high-speed, RF Digital to Analog converter (RF DAC). The DPG2 automatically formats the data and sends it to the AD9129-CBLTX-EBZ, simplifying evaluation of the device. The Evaluation Board (EVB) runs from +5 volt and +8 volt supplies. Figure 2 is an image of the top side of the AD9129 EVB.
AD9129 Evaluation Software
The AD9129 Evaluation Board software has an easy-to-use graphical user interface (GUI). It is included on the Evaluation Board CD, or can be downloaded from the DPG Web site at http://www.analog.com/dpg. This will install DPGDownloader (for loading vectors into the DPG2) and the AD9129 SPI Controller application.
Hardware Setup
Connect +5V to P3, GND to P4, and +8V to P5. The evaluation board connects to the DPG2 unit through connectors P1 and P2. The spectrum analyzer should connect to the N-connector at J1. Because cable systems are typically 75 Ω systems, the output of the board is also 75 Ω. For best results using a 50 Ω spectrum analyzer, a transformer should be used to transform the output impedance from 75 Ω to 50 Ω. The PC should be connected to the EVB using the mini-USB connector XP2 after installation of the Evaluation Board software.
Figure 1 - Block diagram of the AD9129 lab bench set-up
Figure 2 - Top view of AD9129-CBLTX-EBZ Evaluation Board
Getting Started
The PC software comes on the included Evaluation Board CD, but may also be downloaded from the DPG Web site at http://www.analog.com/dpg. The installation will include the DPG Downloader and ADF4350 programming software as well as all the necessary AD9129 files including schematic, board layout, data sheet, SPI GUI, and other files. The following procedure will set up a basic 1-carrier, 256-QAM signal.
Initial Set-Up
1. Install the DPG Downloader, ADF4350, and AD9129 software and support files on your PC 2. Start the AD9129 Control Panel GUI (but don’t hit the run arrow yet) 3. Connect the EVB to your PC and lab equipment as shown in Figure 1 above. Use a USB cable to connect your PC to the EVB, and another USB cable to connect your PC to the DPG2 unit. Note that a DPG3 unit can also be used. 4. Start the ADF4350 SPI for AD9129 It is suggested that the basic set-up is verified before making any modifications to the evaluation board.
Load Initial Settings
To begin, open the AD9129 SPI application (Start > Programs > Analog Devices > AD9129 > AD9129_27 SPI). The screen should look similar to Figure 3 on the Common tab. The AD9129 SPI loads default settings that should be usable for most applications.
Figure 3. Entry screen of the AD9129 SPI GUI
Configure Hardware
Configure the hardware according to the hardware set-up instructions given in the Hardware Setup section above. The spectrum analyzer can be configured with Start Frequency = 20 MHz, Stop Frequency 1 GHz, and Resolution Bandwidth of 100 kHz. Use an Average/RMS detector setting, and choose Input Attenuation to be 10 dB. This can be adjusted later if indications are that the analyzer is causing degradations (warnings on the analyzer itself, or third order products appearing on the output spectrum.). The potentiometer should be tuned so that VAGC, the automatic gain control voltage for the power amplifier, is 1.2 V to replicate the following example measurements.
Program the PLL
Open the ADF4350 SPI application (Start>Programs>Analog Devices> AD9129>ADF4350 SPI for AD9129) that programs the external PLL on the board. The screen should look like Figure 4 on the Main Window tab.
Figure 4. Main Window of the ADF4350 SPI GUI
The PLL and the chosen reference crystal do not allow for as much frequency precision as the DPG, which specifies its sample frequency down to tens of Hertz. A suggested accuracy for this evaluation board is 100 kHz. To achieve this level of precision, the “Reference Divider” is changed to 250 so that the “PFD Frequency” changes to 0.100 MHz. Then, in the “RF Frequency” section, the “Output Frequency” box should be changed to 2305 MHz to most closely match the DPG sample frequency of 2.30503091 GHz. The discrepancy between the data sample frequency and the programmed clock frequency may create some low level distortion, but the effects have proven negligible in lab. The rest of the settings may be left in their default states. Click the “Write All Reg” button, and the boxes along the bottom of the screen should change from green to grey, indicating that the registers have been programmed.
Enable the PLL
On the “PLL” tab, the “Controller Ena” button should be green. Click the “Play” button (Arrow to the right) to program the registers. The Readback light next to the button should change from red to green, and the PLL LOCK light should turn green. Note that in some cases, it may be necessary to click the “Controller Reset” button (it goes to green), click the “Play” button, and then click the “Controller Reset” button (it goes to red) and the “Play” button again to reset the PLL in order for it to lock.
Figure 5. PLL screen of the AD9129 SPI GUI
resources/eval/dpg/ad9129-cbltx-ebz.1347630150.txt.gz · Last modified: 14 Sep 2012 15:42 by Dan Fague