Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design

Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design
Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Josh Carnes Mark Rives Data Conversion Systems 2 Worldwide FAE Meeting
Delivered by: Mark Rives, Josh Carnes

Outline WaveVision 5 Software WaveVision 5 Hardware ADC14DS105KARB
WaveVision 5 + ADC14DS105KARB Demo Analog Bowl Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software Overview
Completely new non-Java-based GUI Improved accuracy New features Multiple plot windows Multiple traces Improved plot annotations Continuous capture Averaging Signal generators Exclusion masks New window functions DLL manages the hardware interface so other software can easily access data from our evaluation boards The WaveVision software has been completely re-written to be faster, more accurate and to provide many new features. In the past customers have requested the ability to perform automated captures and interface our capture hardware with their own systems. The new WaveVision 5 software supports this with a dynamically linked library (DLL). The DLL manages all interaction with the WaveVision hardware including loading the right FPGA image, setting the right FPGA voltage, formatting captured data and supporting DUT register access. Other software like LabView, VEE, Matlab and Python can access the DLL through a standard API just like the WaveVision 5 GUI we provide. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software Multiple Windows
Multiple windows can be used to capture data The WaveVision 5 GUI now supports multiple plot panels which can be rearranged in the main window or dragged out onto the Windows desktop. Each plot window includes the ability to add plot information that is stored with the data. This is useful for describing the test setup and conditions used to collect the data. Annotations can be added to the plot and there are several options for exporting the data or just the plot as a graphics file. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software Multiple Traces/Channels
Multiple traces can be viewed on 4 different “channels” View performance of all channels simultaneously Multiple traces up to 4 can be added to each plot window. Complex groups of traces can be saved for later recall. Using the ‘right click’ menu allows the plot readouts to be viewed as shown. This is a good example that shows how different amplitude signals can be captured to different traces for easy comparison. The key dynamic measurements are all summarized in the plot readouts. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software The New Math
FFT routines based on the same Matlab code used internally by design and apps. Interpolated fundamental location Improved harmonic location Improved accuracy Cosine windows: 4, 6 and 11-term Programmable number of harmonics observed Programmable bin exclusion at DC, fundamental and harmonics User specified exclusion regions Phase noise removal Spurious removal Some large benefits of the new WaveVision 5 software are the new internal math functions that analyze the data. Matlab scripts used internally by our design and applications engineers have been polished and translated into the code to provide accurate, expected results for performance metrics such as the SNR, average noise, THD, SFDR, and SINAD Some of the big improvements over the WV4 software are related to analysis accuracy when capturing non-coherent data. When the frequency is not bin centered, the accuracy of finding large order harmonics of the fundamental is poor, so we use a form of interpolation to more accurately find the fractional value of the fundamental between bins. This greatly enhances the finding of harmonic locations and improves performance metric accuracy because the interpolation also gives a more precise value of the fundamental power. A new family of cosine windows are also added to analyze non-coherent data, giving more accurate, consistent results. Many analysis options are included to tailor your analysis to the desired spectrum. For instance, you can change the number of harmonics that are considered by the software to be distortion, and you have control over exclusion regions around DC, the fundamental, and harmonics that you know should not contribute to the SNR. These exclusion regions are especially important when using windowing functions, and when test setup related noise and distortion are corrupting the spectrum. Phase noise and spurious tones are two examples of spectrum corruptions that can be caused by the test setup Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software Omitting Bins in Calculations
Bin omissions remove the effects of DC offsets and windowing function lobes from calculations Omit near Harms Omit near Fund Omit near DC As mentioned on the previous slide, bins often need to be excluded or omitted in calculations to achieve accurate results. WV5 omits 3 different TYPES of regions including: Bins near DC, Bins near the fundamental tone, and bins near harmonics. The arrows pointing to the figure in this slide illustrate these 3 types of regions. The primary purpose of these bin omissions is to enhance the accuracy when using windowing functions. When a window is used, tones in the spectrum including the DC offset, fundamental, and harmonics, are spread into Lobes that span a number of bins. In an ideal spectrum we only expect tones, and not Lobes, so the width of the Lobes can cause incorrect results in analysis functions. For instance, an SFDR routine might accidentally find a point in the lobe of the fundamental to be spurious distortion. The bin omissions correct these problematic scenarios. With these bin omissions, the indicated bins are not used in calculations, but in cases where the bandwidth of noise is important, such as with the SNR, the omitted bins are “back-filled” with a power value equal to the average power of the non-omitted noise bins. In the WV5 FFT control box, the circled settings can be used to change the number of exclusion bins on either side of DC, the fundamental, and harmonics Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software Omitting Bins in Calculations
FFT exclusion areas allow the flexibility to define regions that are excluded from calculations R-click Phase Noise Exclusion SNR without exclusion = 71.1 dBFS SNR with exclusion = 73.3 dBFS To be clear, there are two ways that bins can be omitted in analyses: 1) Using the bin omission configuration shown in the previous slide 2) Painting your own exclusion area This slide describes how and why you can paint your own exclusion area. In some measurement cases, part of the spectrum can be corrupted by a non-idealities in the test setup. In these cases you may want to correct this part of the spectrum. You can do this by “painting” an exclusion area. An exclusion area forces the analysis function to ignore noise, and spurious tone bins in the spectrum within the painted region. The fundamental and identified harmonics will NOT be ignored. The bins in the painted exclusion area is then back-filled with the average noise value of the non-excluded noise bins. A phase noise example illustrates an effective use of an exclusion. In the diagram you can see a large amount of phase noise surrounding the fundamental. By painting an exclusion mask on this area, the phase noise is excluded without excluding the fundamental to give a more realistic value for the SNR performance of the ADC if the clock jitter were not present in the test setup. Without using the exclusion area, the SNR is calculated to 71.1 dBFS but when the exclusion area is used, the SNR improves to 73.3 dBFS, over 2 dB of improvement. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software Specifying Harmonics
Specifying the harmonics (up to 25) controls the distortion contributions to the THD Fractional interpolation gives improved location accuracy The WV5 software can find up to 25 harmonics of the fundamental. Controlling the number of harmonics that are found will ensure that the necessary bins are interpreted as harmonic distortion to be added to the THD. These bins are also omitted from the SNR calculation. Once again we mention that the fractional interpolation mathematics included in WV5 more accurately finds the frequency location of non-coherent data, therefore improving the location of high-order harmonics. From the graph it can be seen that the harmonics, along with the fundamental tone and the tone that sets the SFDR are identified by blue vertical markers Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software Windowing Functions
New family of windows yields more consistently accurate results 4-term, 6-term, and 11-term Cosine windows Very good sideband suppression Higher order gives more sideband suppression but larger main lobe Window Side-lobe suppression 4-term 98 dB 6-term 153 dB 11-term 290 dB When capturing data with a clock source that is not coherent with the signal source, the fundamental tone will not appear centered on an FFT bin causing large skirts and energy leakage into the surrounding spectrum. Engineers use windowing functions to alleviate this problem. Typical windows that are used by engineers to analyze non-coherent data include the Blackman, Hanning, and Hamming windows. Important specifications for windows include the main lobe bandwidth and the side-lobe suppression. For our purposes of testing high resolution ADCs, side-lobe suppression is the more important factor, and the windows previously mentioned are not always good enough. In WV5 we add a new family of windows that include the 4-term, 6-term, and 11-term Cosine windows. These give excellent side-lobe suppression, with the 11-term giving a whopping 290 dB of range. The drawback is the increase width of the main lobe as can be seen from the graph above where the Cosine Windows are the large 3 of the plotted main lobes. When capturing a 1 kilo-sample FFT, the main lobe width may be limiting, but when using a typical 32k sample in WV5, using these Cosine windows gives the most accurate, consistent results. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software SNR
SNR is the sum of all FFT bins except: DC Fundamental N Harmonics In the next few slides we cover the basics of how the WV5 software calculates SNR, SINAD, THD, and SFDR The SNR is found by excluding the DC, fundamental, and identified harmonic bins, summing the rest of the power, and then converting the power to positive decibels (dB). Note that this is relative to full-scale, or units of dBFS. As mentioned previously, a correction is also made to back-fill excluded bins with the average noise level to get a more accurate SNR number. When the SNR is desired in dB with respect to the carrier, or dBc, the power of the carrier relative to full scale is added to the SNR value in dBFS: SNR [dBc] = SNR [dBFS] + Fundamental_power [dBFS] * Note that Fundamental_power [dBFS] is typically a negative number Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software SINAD
SINAD is the sum of all FFT bins except: DC Fundamental The SINAD is calculated similar to the SNR, except that the harmonic distortion is left in the summation. From the diagram you can see that the harmonic terms are not excluded like the fundamental and DC bins Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software THD
THD is the sum of N Harmonics The THD is the sum of the harmonic terms, and can be expressed in units of dBFS or dBc similar to the SNR, but is reported as a negative number for traditional reasons. Remember that the number of “identified” harmonics can be configured in WV5 software, so any harmonics that are not found and marked with the blue marker will not be included in the THD calculation. Unidentified harmonics will instead be considered noise that will be included in the SNR. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software SFDR
SFDR is the difference between the fundamental and the next biggest signal in the FFT The SFDR can also be given in dBFS or dBc. Relative to the carrier (dBc), the SFDR is calculated as the different between the fundamental and the largest spurious tone on a dB scale. Note that the largest spurious tone is not necessarily a harmonic of the fundamental. Relative to full-scale (dBFS), the SFDR is calculated as the difference between full-scale and the largest spurious tone. Using the fact that full-scale should always be normalized to 0 dB, the dBFS value is simply the absolute power value of the spurious term in dB. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software SFDR Errors
Sometimes signals near DC can appear as SFDR. Adjust the ‘Bins to omit at DC’ to correct. Low frequency information near DC may affect the SFDR. The importance of exclusion bins is easily shown in this example where the SFDR is calculated. In this zoomed-in graph of a frequency spectrum it is seen that a windowing function has caused the DC offset to become a large lobe at DC and that the SFDR is found to be part of this lobe. In this case, the ‘Number of bins to omit near DC’ has not been set high enough. Increasing the bins omitted near DC will force the SFDR analysis function to ignore the near-DC lobe and find the next largest tone. zoomed-in view Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software Noise Floor
Integrated Noise Floor is SNR expressed in dBFS / Nyquist or all the noise integrated from DC to Nyquist Average Noise Floor is the SNR expressed in dBFS / bin and is roughly the displayed average noise level of the FFT Some nice visual tools in the WV5 software include the integrated noise and average noise lines that can be superimposed on top of the spectrum. The integrated noise of the data capture is tightly related to the SNR of the ADC. The integrated noise is defined here as the sum of the noise in the system from DC to Fs/2 relative to full-scale and is in fact the negative of the SNR in dBFS. This quantity is valuable because you can visualize how much dynamic range the system has. If the fundamental falls below the integrated noise line, then the signal to noise ratio is less than 1 and the signal becomes swamped with noise. Without digital filtering, the signal is basically unrecognizable. The average noise line indicates the average value of the noise in the system and cuts through the middle of the noise on the graph. This line can also be considered as the power spectral density of the system scaled by the frequency width of one FFT bin. The units of this value has units of dBFS/bin. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software Continuous Capture
Continuous capture allows observation of stimuli changes in near real-time Update rate dependent on # samples per capture Future updates to WaveVision 5 capture board will enhance speed/update rate Continuous capture uses a lot of processor time, making GUI less responsive A very attractive feature of the WV5 software is the ability to capture and display results in near-real time. When continuous capture is activated, the WV5 hardware board captures and transmits data as fast as possible, and the software GUI updates with each capture on the computer screen. This is particularly affective for debugging devices and their test setups because you can easily observe changes made to the system such as frequency changes, amplitude changes, or even configuration tweaking like changing bias currents and filter bandwidths. The update rate depends on the number of samples per capture but is quite fast for even 32k captures. Future updates to the WV5 capture board hardware and software will improve speed even further. Unfortunately the function is processor intensive and can make the GUI less responsive Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software FFT Averaging
Averaging can be enabled when continuous capture is active Averaging smoothes the noise floor in the FFT, making small signals easier to see Averaging disabled Averaging enabled When continuous capture is active, another interesting feature can be enabled: FFT averaging In a typical, single capture FFT, the noise bands can have wide variations and harmonics can change from capture to capture or hidden in the noise, so FFT averaging allows the user to clarify the spectrum. By taking multiple capture in continuous capture mode, the noise variation across the spectrum tightens and reveals a more distinguishable noise density and clearer, more consistent distortion terms. Despite the clarity of the spectrum and the ability for FFT Averaging to reveal some harmonics that are not typically visible, a noise floor is still a noise floor so distortion below the noise is still not observable. One must record more samples per capture to observe smaller harmonics. One interesting observation from the graphs on this slide is that you can more clearly see the shape of phase noise around the fundamental when FFT averaging is enabled Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Software Average Noise Floor
Observed average noise Calculated average noise When using a windowing function, the observed average noise is higher than the calculated (correct) average noise The difference is window gain in dB To place the fundamental peak at the proper power level, the entire spectrum is normalized by the window gain, causing an upward shift in the average noise floor There is one caveat when applying FFT averaging to non-coherent data captures. From the graph above you can see clearly that in this example the observed average noise does not match the calculated noise. The calculated average noise is indeed the correct answer, but because a windowing function must be applied to non-coherent data, a upward shift in the observed average noise will occur. The cause of this is related to representation of the fundamental as a Lobe, which we talked about before. The entire energy of the fundamental is stored within this lobe that spans many FFT bins, so to maintain the same amount of power as a similar, coherent tone that is centered on a bin, the maximum value of the Lobe is less. This difference between the maximum value of the lobe and the power within the lobe is called the window gain. We want WV5 to be as user friendly as possible so we decided that we wanted the maximum value of the fundamental lobes to always be at the correct value as if all the power was in one bin for ease of observation, so the entire spectrum is scaled by the window gain to force this condition. The observed noise floor, which is most apparent during FFT averaging, is higher than the calculated average noise by the window gain in dB as a result. As you might expect, when the data is coherent, then no window (or more accurately a rectangular window) can be used. In this case the window gain is 1, the spectrum is not scaled, and the observed noise floor is equal to the calculated noise floor. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Hardware Features
Transfers data rapidly at high-speed with USB 2.0 (USB1.1 compatible) Provides jumperless plug-and-play configuration Supports a wide variety of ADC Evaluation Boards including many WaveVision4 compatible evaluation boards Fast data capture 36 parallel CMOS signals at up to 100 MHz (DDR mode) 28 parallel LVDS pairs at up to 375 MHz (DDR mode) 12 differential serial pairs in dual-lane CDF at up to 400 MHz (DDR mode) Base memory capable of storing 64k, 16-bit wide samples DUT control through SPI interface The new WaveVision 5 hardware provides support for both parallel and serial LVDS signals in addition to the CMOS signals supported by previous WaveVision hardware. ADCs with LVDS outputs like the ADC14DS105 and ADC14V155 families of parts require WaveVision 5 hardware for data capture. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Hardware Block Diagram
Each DUT board includes an EEPROM that uniquely identifies its output data format and any other special settings. The Cypress microcontroller on the WaveVision 5 board reads this EEPROM, communicates the results to the DLL running on the PC and the DLL then downloads the appropriate firmware and FPGA image. The FPGA images may store the captured data in on-chip RAM or for applications that require large capture buffers (copier AFEs) external RAM may be populated. The interface to the PC is USB 2.0 with USB 1.1 compatibility. Data may be loaded into the USB pipe under the control of the Cypress microcontroller (slow) or it may be loaded directly into the USB end point FIFO (fast). New products include the faster FIFO support while older products will be migrated as time allows. The transfer speed is most noticeable when doing continuous captures. Each DUT board typically includes its own power input. The WaveVision 5 board does not normally provide DUT power. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 Hardware PCB Photo
CMOS + Low Speed LVDS I/O Power Input Futurebus Power Switch HM-Zd USB 2.0 Here you can see the two primary data capture connectors. The Futurebus connector is fully compatible with WaveVision 4 hardware and supports both CMOS and parallel LVDS signals. The HM-Zd connector is a very high speed differential connector and is used for serialized LVDS data. Both connectors allow access to the DUT EEPROM and provide SPI access to the DUT registers. The standard WaveVision 5 board includes a Xilinx FPGA with ‘LX25’ in the part number. The extended version will have the four external RAMs populated (4 BGA footprints, unpopulated in this photo). IMPORTANT NOTE: Some early WaveVision 5 Rev A boards with ‘LX15’ in the FPGA part number were shipped to the field. If you find one of these boards please return it to Gary Crown. These boards are not supported and it can take a significant amount of time to realize that the wrong FPGA is the root cause of field issues. High Speed LVDS I/O Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 + ADC14DS105KARB Demo Analog Bowl Reference Board Naming Convention: NSIDs for new reference boards use the following letter codes followed by ‘RB’: A = Amplifier D = DVGA F = Filter K = LMK clock device M = Mux V = VGA Xn = Multiple devices For example, the ADC14155 ADC + LMH6515 DVGA reference board: ADC14155DRB The ADC12DL080 + LMH6552 Amplifier + LMH6515 DVGA: ADC12DL080ADRB Two ADC ADCs interleaved on the same board: ADC083000X2RB The ADC14V155 ADC + LMH6515 DVGA + LMK03001C reference board: ADC14V155KDRB The ADC14DS105 ADC + LMH6552 Amplifier + LMK02000 reference board: ADC14DS105KARB Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Near-Zero IF Receiver Requirements
3G Wireless Receiver ADC Sample Rate Msps Input Frequency < 40 MHz Input Signal Bandwidth < 20 MHz > 70 dB SNR > 80 dB SFDR Dual ADC for Quadrature (I/Q) Processing As component performance has increased we can now implement radio receivers where the RF signal is directly mixed to baseband (DC) in a single mixing stage. This approach minimizes the number of RF components but provides some additional challenges. In order to simplify the subsequent digital processing many designs mix the RF carrier to a frequency near zero. The ADC must be able to provide sufficient SNR to resolve small signals in the presence of large interfering (blocking) signals. It must also provide sufficient spurious free dynamic range (SFDR) so that distortion products do not mask the desired signal. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

ADC14DS105KARB Near-Zero IF Receiver Reference Board
This figure includes the block diagram of our Reference Board based on our ADC14DS105 high performance A/D Converter, our LMH6552 high frequency, high performance differential amplifier, and our LMK02000 precision clock conditioner with integrated PLL. The RF signal must be passed through a band-limiting filter then an LNA and then a quadrature demodulator prior to our reference board. The resulting analog quadrature (I/Q) data stream must be low-pass filtered and then digitized. The Low Intermediate Frequency (IF) reference board provides the necessary amplification and low-pass filtering required to process the quadrature demodulator (mixer) outputs prior to digitization. The LMH6552 is a current feedback differential amplifier that has excellent noise and distortion performance. It can be used with a differential input or it can be used to convert a single-ended input to a differential output. The gain can be adjusted to set the maximum RF input level to the ADC full-scale voltage. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Amplifier + ADC Circuit Implementation
A low pass filter after the amplifier: Attenuates alias images Reduces broadband noise from the amplifier The implementation of the LMH6552 driving the input of the ADC14DS105 is show here. The LMH6552 fully differential amplifier is used as a single-ended to differential conversion circuit with gain. The common mode output voltage of the LMH6552 is identical to its VCM pin, which is connected to VCOM output of the ADC14DS105. The low pass filter after the amplifier attenuates images and limits the noise that may come from the amplifier. In systems where the source impedance is low (< 100 ohms) the LMH6552’s current feedback topology can offer a significant noise improvement over competitive voltage feedback amplifiers. If the source impedance is high the noise performance will not be as good. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Anti-Alias / Noise Filter Response
The response of the noise filter shown on the previous page shows a -3dB corner near 35MHz. Both channels are closely matched. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

ADC14DS105 Dual 14-bit 105 MSPS ADC
Features Clock Duty-Cycle Stabilizer Single 3.0V or 3.3V Power Supply Output Data Format Single or dual lane LVDS for each channel with shared Clock and Frame signals Serial Control Interface Over-range Outputs Differential Inputs Internal Voltage Reference 1 GHz Full Power Bandwidth 60-pin LLP package (9mm x 9mm) Key Performance Metrics Resolution: bits Conversion rate: MSPS Fin = 10MHz SNR dBFS SFDR dBFS SINAD dBFS Fin = 240MHz SNR dBFS SFDR dBFS SINAD dBFS Power consumption Normal Operation: 1W (typ) The features and specifications of the ADC14DS105 shown here indicate its leading edge performance at low power consumption for its resolution and performance. Note that the ADC14DS105 has specifications for input frequencies up to 240 MHz and that performance holds up quite well as input frequency increases. In this low-frequency application the wide input bandwidth of the ADC provides excellent performance. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

ADC14DS105 + LMH6552 Output Spectrum
Fin = 20 MHz Fs = 100 MSPS The output spectrum of the ADC14DS105/LMH6552 combination shows that the amplifier has not reduced the system SNR. The ADC’s typical SNR for Fin = 10MHz is 73dBFS and the combined system provides SNR of 73.2dBFS. The lowpass filter will also reduce harmonics at the amplifier’s output. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

ADC14DS105 KARB Performance vs. Fin
Fs = 100 MSPS The performance of the ADC14DS105/LMH6552 combination over input frequency is very good. This data was taken with our reference board, so also indicates the excellent performance of the LMK02000 clock conditioner. Spending more time fine tuning the PCB layout and the filter topology will probably enable SFDR > 90dBFS from 1MHz to 25MHz. E Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

ADC14DS105KARB Near-Zero IF Receiver Reference Board
LMK02000 LMH6552 +/- 5V Power LMH6552 LMK02000 Programming Header ADC14DS105 Reference Oscillator 700Mbps Serial Interface This photos shows the ADC14DS105KARB reference board and identifies the major components. VCXO Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

ADC Test Environment As with most of our evaluation boards the quality of the signal source is critical. Some good signal sources include the HP/Agilent 8644B, R&S SME, Fluke 6080A and the new R&S SMA100A (best broadband phase noise available today). Even with a good signal source a filter is still required to remove any harmonics and broad band noise. The Trilithic tunable bandpass filters are an excellent choice with 90dB of stop-band attenuation up to H3 and an octave tuning range. The WaveVision 5 board will come with a USB cable and a power supply. A separate supply will be required for the DUT board and varies from board to board. Typically +5V at 1A will be sufficient if the board includes regulators for lower voltages (most do). Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

ADC Test Environment Live Demo
Lab Setup Live demo of the ADC14DS105KARB + WaveVision 5 hardware and software. The bandpass filter is critical when making high accuracy measurements. It removes the harmonics from the signal source and reduces the broadband noise. In some cases there may a noise bump around the desired signal where the signal generator noise floor can be seen in the filter pass band. The previously described exclusion mask can be used to remove the effect of this noise from the signal source. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Reference Board Setup Notes
The PIC board is used to program the LMK02000 Switch 1 = OFF Switch 2 = OFF The ADC14DS105KARB and ADC14V155KDRB require a small board with a PIC microcontroller on it to load the LMK PLL registers. Alternatively the Code Loader software and interface cable can be used to program a wider range of frequencies in the LMK devices. Once the setup is running and the WaveVision 5 GUI is started the ADC registers can be programmed as shown above. The registers are located on a tab at the right side of the main WaveVision window. The number format (two’s complement / offset binary) must be set the same in the ADC14DS105 registers and the WaveVision 5 GUI (Signal Sources tab on the right side). Place JP1 on main board to provide power to PIC board Align Arrows Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

WaveVision 5 + ADC14DS105KARB Demo Analog Bowl Before we dive into the Analog Bowl questions, let’s briefly recap what we’ve covered in this seminar. First We wrapped up with a review of our cooperative efforts with other groups within National which are aimed at emphasizing to customers the complementary benefits of using our signal path solutions together in a system. It’s a lot of material to absorb in a short time, so please feel free to contact either Mark Rives or Josh Carnes with any questions you might have regarding this presentation or other more general high-speed ADC applications. Now, let’s move on to the Analog Bowl questions and see how well did in presenting this material. Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Analyze the Low-IF Receiver Reference Design
Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design Which of the following is a good use of the WaveVision 5 software exclusion areas Completely excluding all noise from a region of the spectrum in calculations Estimating the processing gain of a digital filter Removing phase noise from the SNR Excluding harmonic tones from the THD Correct: C 10 Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Which windowing function gives the most sideband suppression
Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design Which windowing function gives the most sideband suppression 4-term Cosine window 6-term Cosine window 11-term Cosine window They all have the same suppression Correct: C 10 Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

What is a benefit of FFT averaging in the WaveVision 5 software
Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design What is a benefit of FFT averaging in the WaveVision 5 software It reduces the noise floor It smoothes the noise floor It creates a perfect power spectral density It uncovers all the harmonics Correct: B 10 Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design In the WaveVision 5 software, what is the difference between the observed and calculated average noise? No difference The windowing function gain in dB 3 dB 6 dB Correct: B 10 Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Which specification is not sufficient for a 3G Wireless receiver?
Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design Which specification is not sufficient for a 3G Wireless receiver? Sampling clock = 100 MHz SNR = 67 dB SFDR = 82 dB Input signal bandwidth = 40 MHz Correct: B 10 Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design What is the disadvantage of setting the # of harmonics too low in the WaveVision 5 software: Harmonics are found at incorrect locations Increased THD Increased SNR Increased SINAD Correct: C 10 Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design Which of these is not a purpose of including a LP filter between the amplifier and ADC on the ADC14DS105KARB board? The filter attenuates alias images for all input frequencies in the passband The filter attenuates harmonics for all input frequencies in the passband The filter reduces broadband noise from the amplifier The filter reduces switching kickback from the ADC into the amplifier Correct: B 10 Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design When the input amplitude is small (-20dBFS), the SNR performance of the ADC14DS105KARB board is limited mostly by what? Quantization noise from the ADC Thermal noise from the ADC Thermal noise from the Amplifier Jitter from the clock Correct: B 10 Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

In units of dBFS, the SFDR is defined as what?:
Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design In units of dBFS, the SFDR is defined as what?: The ratio of the fundamental power [dB] to the largest spurious tone [dB] The difference of the full scale power [dB] to the largest harmonic tone [dB] The difference between the full scale power [dB] and the largest spurious tone [dB] The difference between the fundamental power [dB] and the largest harmonic tone [dB] Correct: C 10 Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

What may limit the update rate for continuous capture:
Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design What may limit the update rate for continuous capture: The USB interface Sample size CPU speed Cypress firmware All of the above Correct: E 10 Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Team Scores Team 1 Team 2 Team 3 Team 4 Team 5

52 Worldwide FAE Meeting Delivered by: Mark Rives, Josh Carnes

Using WaveVision 5 to Analyze the Low-IF Receiver Reference Design

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