【摘要】：光子相關(guān)光譜技術(shù)作為測量納米顆粒粒徑及其分布的主要方法,在納米顆粒測量領(lǐng)域得到了廣泛應(yīng)用。光子相關(guān)器是光子相關(guān)光譜測量系統(tǒng)的核心裝置,通過對光子脈沖計數(shù),并進(jìn)行實時自相關(guān)運算得到散射光強(qiáng)的時間自相關(guān)函數(shù)。目前國內(nèi)使用的光子相關(guān)器多為進(jìn)口產(chǎn)品,因此,設(shè)計開發(fā)具有自主知識產(chǎn)權(quán)的大動態(tài)范圍高速光子相關(guān)器具有重要的經(jīng)濟(jì)和社會效益。 本文圍繞擴(kuò)大相關(guān)器動態(tài)范圍、提高相關(guān)器運算速度及相關(guān)函數(shù)的歸一化精度,進(jìn)行了以下研究工作： (1)基于光子相關(guān)光譜理論,研究了線性光子相關(guān)器、比例光子相關(guān)器及多采樣時間光子相關(guān)器的結(jié)構(gòu)和優(yōu)缺點。 (2)采用FPGA設(shè)計了雙光子計數(shù)器對光子脈沖信號進(jìn)行交替計數(shù),實現(xiàn)了無縫隙光子計數(shù)；利用DSP片內(nèi)大容量存儲器設(shè)計了環(huán)形移位寄存器,實現(xiàn)了大動態(tài)范圍比例相關(guān)器；PC機(jī)和DSP之間通過USB接口進(jìn)行數(shù)據(jù)傳遞；提出了比例相關(guān)器中通道延遲時間的計算公式；分析了相關(guān)函數(shù)的歸一化方法。 (3)分析了多采樣時間相關(guān)器的工作原理；采用FPGA設(shè)計實現(xiàn)了高速多采樣時間相關(guān)器,其核心模塊為相關(guān)運算模塊,由移位寄存器、乘法器、累加器以及數(shù)據(jù)類型轉(zhuǎn)換器組成,各部分均采用Verilog語言編程實現(xiàn)；研究了相關(guān)函數(shù)的三角平均影響及相關(guān)函數(shù)的歸一化方法。 (4)基于DSP的比例相關(guān)器擴(kuò)展了動態(tài)范圍,基于FPGA設(shè)計了相關(guān)器的高速相關(guān)運算通道,提高了相關(guān)運算速度,采用DSP+FPGA相結(jié)合的結(jié)構(gòu)實現(xiàn)了大動態(tài)范圍高速光子相關(guān)器。 (5)采用本文設(shè)計的大動態(tài)范圍高速光子相關(guān)器組成光子相關(guān)光譜顆粒測量裝置,在25℃溫度下,分別對60、150、200、300及450nm五種標(biāo)準(zhǔn)聚苯乙烯顆粒進(jìn)行了實測。測量結(jié)果表明,本文設(shè)計的相關(guān)器能夠提高測量結(jié)果的準(zhǔn)確性,選擇合適的采樣間隔和動態(tài)范圍可使測量結(jié)果的相對誤差小于5%,重復(fù)性誤差小于3%,完全滿足納米顆粒測量的需要。 本文在研究光子相關(guān)光譜理論、光子相關(guān)器結(jié)構(gòu)和相關(guān)函數(shù)的歸一化方法基礎(chǔ)上,采用DSP+FPGA相結(jié)合的結(jié)構(gòu)實現(xiàn)了大動態(tài)范圍高速光子相關(guān)器,最小采樣間隔為100ns,實現(xiàn)的動態(tài)范圍可達(dá)1010。
[Abstract]:As the main method to measure the particle size and its distribution, photon correlation spectroscopy has been widely used in the field of nano-particle measurement. Photon correlator is the core device of photon correlation spectrum measurement system. The time autocorrelation function of scattered light intensity is obtained by counting photon pulses and performing real-time autocorrelation operation. At present, most of the photon correlators used in China are imported products. Therefore, the design and development of large dynamic range high-speed photon correlators with independent intellectual property rights has important economic and social benefits. In this paper, we focus on expanding the dynamic range of correlator and improving the speed of correlator operation and the normalization precision of correlation function. The following work has been done: (1) based on the theory of photon correlation spectrum, the linear photon correlator is studied, and the linear photon correlator is studied. The structure, advantages and disadvantages of proportional photon correlator and multisampling time photon correlator. (2) the two-photon counter is designed with FPGA to count the photon pulse signal alternately, and the gap-free photon count is realized, the loop shift register is designed by using the large-capacity memory in DSP chip, and the proportional correlator with large dynamic range is realized. The data transfer between PC and DSP is carried out through USB interface, the formula of channel delay time in proportional correlator is proposed, and the normalization method of correlation function is analyzed. (3) the working principle of multi-sampling time correlator is analyzed. The high-speed multi-sampling time correlator is designed and implemented with FPGA. The core module of the correlator is the correlation operation module, which consists of shift register, multiplier, accumulator and data type converter. Each part is programmed in Verilog language. The influence of trigonometric mean of correlation function and the normalization method of correlation function are studied. (4) the proportional correlator based on DSP extends the dynamic range, designs the high-speed correlation channel of the correlator based on FPGA, improves the speed of correlation operation, and realizes the high-speed photon correlator with large dynamic range by using the structure of DSP FPGA. (5) using the high-speed photon correlator designed in this paper, five kinds of standard polystyrene particles (60150 200300 and 450 nm) were measured at 25 鈩，

本文編號：2444216