NI矢量信號(hào)收發(fā)器的FPGA編程

VST Streaming項(xiàng)目樣例提供兩個(gè)主機(jī)樣例。較簡(jiǎn)單的一個(gè)樣例把從VST處采集得到的增多的或者連續(xù)的波形數(shù)據(jù)傳輸至VST進(jìn)行生成，。比較高級(jí)的樣例說明了多個(gè)VST的MIMO同步。

圖 16.這些樣例說明了VST Streaming項(xiàng)目樣例的主機(jī)接口

4. 儀器驅(qū)動(dòng)FPGA擴(kuò)展

儀器驅(qū)動(dòng)FPGA擴(kuò)展提供了一種兼容NI-RFSA和NI-RFSG儀器驅(qū)動(dòng)的VST FPGA編程方法。FPGA上的抽取層實(shí)現(xiàn)了所需要的儀器驅(qū)動(dòng)功能，同時(shí)提供接口以改善具體應(yīng)用的FPGA。雖然不像儀器設(shè)計(jì)庫(kù)的直接編程那樣靈活，然而 儀器驅(qū)動(dòng)FPGA擴(kuò)展支持的修改類型與標(biāo)準(zhǔn)信號(hào)分析儀和信號(hào)發(fā)生器的基于記錄的采集和生成模式相一致。

圖 17. 儀器驅(qū)動(dòng)FPGA擴(kuò)展架構(gòu)包含VST儀器設(shè)計(jì)庫(kù)，并且增加了一個(gè)抽取層以保護(hù)組件。用戶IP不在此代碼中，由主機(jī)進(jìn)行控制，并且不受預(yù)編譯封閉源NI-RFSA和NI-RFSG的影響

5. 大型FPGA開發(fā)考慮事項(xiàng)

The Virtex-6 LX195T FPGA on the NI PXIe-5644R and the NI PXIe-5645R is a large FPGA, though the full suite of instrument design libraries consumes a considerable fraction of the available resources. As such, compilation times can take 5 hours or more when using the NI LabVIEW FPGA Compile Cloud Service, depending on the complexity and resource utilization of the FPGA design. Furthermore, FPGA compilation is a non-deterministic process, and as a design consumes more FPGA resources, the repeatable compilation success rate drops below 100%. For such designs, initiating multiple compiles in parallel can help to ensure a successful compilation in approximately the same time as a single compilation. Table 3. provides some estimates for the different FPGA designs discussed in this paper.

表3. 各種VST FPGA設(shè)計(jì)的編譯時(shí)間、成功率和FPGA占用率。