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biblio.bib
... | ... | @@ -185,4 +185,12 @@ |
185 | 185 | year={2002}, |
186 | 186 | publisher={Elsevier} |
187 | 187 | } |
188 | + | |
189 | +@article{andrich2018high, | |
190 | + title={High-Precision Measurement of Sine and Pulse Reference Signals Using Software-Defined Radio}, | |
191 | + author={Andrich, Carsten and Ihlow, Alexander and Bauer, Julia and Beuster, Niklas and Del Galdo, Giovanni}, | |
192 | + journal={IEEE Transactions on Instrumentation and Measurement}, | |
193 | + year={2018}, | |
194 | + publisher={IEEE} | |
195 | +} |
ifcs2018_proceeding.tex
1 | +% JMF : revoir l'abstract : on y avait mis le Zynq7010 de la redpitaya en montrant | |
2 | +% comment optimiser les perfs a surface finie. Ici aussi on tombait dans le cas ou` | |
3 | +% la solution a 1 seul FIR n'etait simplement pas synthetisable => fusionner les deux | |
4 | +% contributions pour le papier TUFFC | |
5 | + | |
1 | 6 | \documentclass[a4paper,conference]{IEEEtran/IEEEtran} |
2 | 7 | \usepackage{graphicx,color,hyperref} |
3 | 8 | \usepackage{amsfonts} |
... | ... | @@ -67,7 +72,7 @@ |
67 | 72 | the non-linear behavior of the downconverter introduces noise or spurious signal aliasing as |
68 | 73 | well as the generation of the frequency sum signal in addition to the frequency difference. |
69 | 74 | These unwanted spectral characteristics must be rejected before decimating the data stream |
70 | -for the phase noise spectral characterization. The characteristics introduced between the | |
75 | +for the phase noise spectral characterization \cite{andrich2018high}. The characteristics introduced between the | |
71 | 76 | downconverter |
72 | 77 | and the decimation processing blocks are core characteristics of an oscillator characterization |
73 | 78 | system, and must reject out-of-band signals below the targeted phase noise -- typically in the |
... | ... | @@ -92,7 +97,7 @@ |
92 | 97 | defining the coefficients and the sample size. For this reason, and because we consider pipeline |
93 | 98 | processing (as opposed to First-In, First-Out FIFO memory batch processing) of radiofrequency |
94 | 99 | signals, High Level Synthesis (HLS) languages \cite{kasbah2008multigrid} are not considered but |
95 | -the problem is tackled at the Very-high-speed-integrated-circuit Hardware Description Language (VHDL). | |
100 | +the problem is tackled at the Very-high-speed-integrated-circuit Hardware Description Language (VHDL) level. | |
96 | 101 | Since latency is not an issue in a openloop phase noise characterization instrument, the large |
97 | 102 | numbre of taps in the FIR, as opposed to the shorter Infinite Impulse Response (IIR) filter, |
98 | 103 | is not considered as an issue as would be in a closed loop system. |
... | ... | @@ -203,8 +208,8 @@ |
203 | 208 | \end{cases} |
204 | 209 | \label{model-FIR} |
205 | 210 | \end{align} |
206 | -To explain the system \ref{model-FIR}, $\mathcal{R}_i$ represents the rejection of depending on $N_i$ and $C_i$, $\mathcal{A}$ | |
207 | -is a theoretical area occupation of the processing block on the FPGA, and $\Delta_i$ is the total rejection for the current stage $i$. | |
211 | +To explain the system \ref{model-FIR}, $\mathcal{R}_i$ represents the stopband rejection dependence with $N_i$ and $C_i$, $\mathcal{A}$ | |
212 | +is a theoretical area occupation of the processing block on the FPGA as discussed earlier, and $\Delta_i$ is the total rejection for the current stage $i$. | |
208 | 213 | Since the function $\mathcal{F}$ cannot be explictly expressed, we run simulations to determine the rejection depending |
209 | 214 | on $N_i$ and $C_i$. However, selecting the right filter requires a clear definition of the rejection criterion. Selecting an |
210 | 215 | incorrect criterion will lead the linear program solver to produce a solution which might not meet the user requirements. |
211 | 216 | |
... | ... | @@ -223,13 +228,17 @@ |
223 | 228 | \end{figure} |
224 | 229 | |
225 | 230 | The objective function maximizes the noise rejection ($\max(\Delta_{i_{\max}})$) while keeping resource occupation below |
226 | -a user-defined threshold. The MILP solver is allowed to choose the number of successive | |
231 | +a user-defined threshold, or aims at minimizing the area needed to reach a given rejection ($\min(S_q)$ in | |
232 | +the forthcoming discussion, Eqs. \ref{cstr_size} and \ref{cstr_rejection}). | |
233 | +The MILP solver is allowed to choose the number of successive | |
227 | 234 | filters, within an upper bound. The last problem is to model the noise rejection. Since filter |
228 | 235 | noise rejection capability is not modeled with linear equations, a look-up-table is generated |
229 | 236 | for multiple filter configurations in which the $C_i$, $D_i$ and $N_i$ parameters are varied: for each |
230 | -one of these conditions, the low-pass filter rejection defined as the mean power between | |
231 | -half the Nyquist frequency and the Nyquist frequency is stored as computed by the frequency response | |
232 | -of the digital filter (Fig. \ref{noise-rejection}). An intuitive analysis of this chart hints at an optimum | |
237 | +one of these conditions, the low-pass filter rejection is stored as computed by the frequency response | |
238 | +of the digital filter (Fig. \ref{noise-rejection}). Various rejection criteria have been investigated, | |
239 | +including mean value of the stopband response, median value of the stopband response, or as finally | |
240 | +selected, maximum value in the stopband. An intuitive analysis of the chart of Fig. \ref{noise-rejection} | |
241 | +hints at an optimum | |
233 | 242 | set of tap length and number of bit for representing the coefficients along the line of the pyramidal |
234 | 243 | shaped rejection capability function. |
235 | 244 | |
... | ... | @@ -303,7 +312,7 @@ |
303 | 312 | |
304 | 313 | The resource occupation when synthesizing such FIR on a Xilinx FPGA is summarized as Tab. \ref{t1}. |
305 | 314 | We have considered a set of resources representative of the hardware platform we work on, |
306 | -Avnet's Zedboard featuring a Xilinx XC7Z020-CLG484-1 Zynq System on Chip (SoC). The results on | |
315 | +Avnet's Zedboard featuring a Xilinx XC7Z020-CLG484-1 Zynq System on Chip (SoC). The results reported in | |
307 | 316 | Tab. \ref{t1} emphasize that implementing the monolithic single FIR is impossible due to |
308 | 317 | the insufficient hardware resources (exhausted LUT resources), while the FIR cascading 5 or 10 |
309 | 318 | filters fit in the available resources. However, in all cases the DSP resources are fully |