共查询到20条相似文献，搜索用时 31 毫秒
1.
This paper introduces a MP3 player solution based on universal microchip, Intel 8 bit microchip. It downloads music by USB interface and stores files into compact flash card. This paper specifies the usb interface technology between microchip and computer, interface design between microchip and compact flash card, and the control method of STA013 ,a mp3 decoding chip. The discrete audio signal is transformed into the continual audio signal by D/A transformer CS4334. Because of using a universal microchip, this system can also be embeded into other microcontrol system to achieve an apparatus with MP3 player. 相似文献
2.
YANG Xue-heng CHEN An HE Guang-hong FENG Xiao-juan WANG Ying-fang ZHAN Jie TANG Zhi-liang 《保鲜与加工》2001,(3):137-141
Some ideas are given about using out-clock, CPU and anti-T-net of D/A card for getting to the intelligent control of scanning voltage ,low-filter and hign-filter of STM; logarithm amplifier for tunnelling current contraction. At last, some applications and questions when it running about STM are discussed. 相似文献
3.
The design of MP3 decode system based on DSP is introduced. TLV320AIC23, a high performance and stereo codec chip, is selected as a D/A converter in the system. Two McBSPs ofDSP are connected to TLV320AIC23, one of them acts as configuration interface, the other ,the audio digital interface. Configuration interfacemode is SPI. The MP3 audio bitstreamtransmissionbetween the PC and DSP isrealized through the USB1.1 interface. So it is convenientto access MP3 audio bitstream. A large capacitymemory device, Compact Flash Card , is a storage media accessing MP3 bitstream.a programmable logical device, CPLD, controls reading, writing and chip selection of USB and Compact Flash Card. Some experiments show the systemcan well accomplish MP3 decodingand playing. 相似文献
4.
为了进一步提高对芋疫病预测预报,科学指导生产上的防治,应用最小二乘法、频次分布、聚集度指标、m*-m回归分析和Taylor幂法则等对病株的空间分布型进行了分析。结果表明:当田间芋疫病病株率在0.427~0.513时,病株田间分布属聚集分布;当田间芋疫病病株率在0.720~0.820时,病株田间分布属均匀分布。此外其病株空间分布的基本成分是个体群,病株个体间相互吸引,病株在大田中存在明显的发病中心,且病株个体的空间格局随着病株密度的提高越趋均匀分。在此基础上,提出了Iwao最适理论抽样模型N=232.3783/m-87.9438,并建立序贯抽样模型T0(N)=0.3689N±1.7177$\sqrt{N}$,即:调查株数N时,若累计病株率超过上界可定为防治对象田,若累计病株率未达到下界时,可定为不防治田,若累计病株率在上下界之间,则应继续调查,直到最大样本数m0=0.3689时,也即病株率15%,所需抽样数542株止。 相似文献
5.
为了明确甘薯大象甲幼虫的空间分布和种群特征。2011年通过对15块甘薯田的调查,应用聚集度指标的计算公式和Iwao的m*-m回归分析法、Taylor的幂法则等,对其空间分布型和田间理论抽样数进行了测定和分析。结果表明：甘薯大象甲幼虫在甘薯田间呈聚集分布。聚集强度与密度相关,聚集强度随着幼虫密度的升高而增强;而个体群所占的空间随密度的升高而减少。导致甘薯大象甲幼虫聚集分布的主要原因是环境因子。在此基础上,建立了幼虫虫口密度调查的最适理论抽样数公式[n=1.962/D2(1.1047/m+0.8737)]和序贯抽样模型[T0(n)=0.2n±0.4759 ]。 相似文献
6.
灰飞虱在水稻田空间分布格局及抽样技术研究 总被引：1，自引：1，他引：0
为了提高对灰飞虱在稻田的监测预报与持续控制水平,应用聚集度指标法、Iwao法和Taylor幂法则,研究了浙西北水稻田灰飞虱的空间分布格局和抽样技术。结果表明,灰飞虱在水稻田呈聚集分布为主,聚集强度随虫口密度增加而增强。其聚集原因经Blackith种群聚集均数(λ)测定,当成虫、成若虫平均虫口密度分别在1.3978头/丛、1.4883头/丛以下时,λ<2,聚集是由周边环境、移栽期、生育期等某种环境因素所引起的;当成虫、成若虫平均虫口密度分别在1.3978头/丛、1.4883头/丛以上时,λ≥2。而若虫：λ均≥2。其聚集因素是由灰飞虱自身特性与环境因子共同作用所引起。以此为基础,提出了理论抽样数和序贯抽样模型：n=(1.96)2/D2(1.35595/m+0.41366)和T(n)= 5n±4.13778 。研究结果为稻田灰飞虱的准确抽样调查和有效防治提供了科学依据。 相似文献
7.
早熟柑橘黄龙病空间格局参数特征及其应用 总被引：1，自引：0，他引：1
为了揭示柑橘早熟宫川黄龙病的空间分布信息和病株行为特征,2004-2009年采取多级抽样法于每年11月上旬在果实成熟期对2块定点样地逐株进行病级调查,取得了12组样本资料,应用聚集度指标法、Iwao 法和Taylor法等对其空间分布型进行测定检验,结果表明柑橘黄龙病在早熟宫川果园呈聚集分布,其聚集强度是随着病级升高而增加。其聚集原因经Blackith种群聚集均数测定,当m<2.1184时,其聚集是由于某些环境如气候、栽培条件、植株生育状况等所引起的;当m≥2.1184时,其聚集是由病株本身的聚集行为与环境条件综合影响所致。在此基础上提出了理论抽样数和序贯抽样模型：n=(1/D)2?[1/m+0.6761] 和Tn=1.831 /[D02-0.1581 /n]。 相似文献
8.
超声波刺激植物生长仪器设计 总被引：1，自引：1，他引：0
超声波技术在生物技术上的运用近年来得到越来越多的关注,在农学和植物学的研究和应用中,超声波刺激对植物的生长发育和次生代谢产物的产生的影响是一个重要方向。本仪器的设计目的是为了用相对简单的实现方式和较少的成本产生具有优秀稳定度和精确度的超声波用于刺激植物植株、种子、组织和细胞等。仪器通过MAX038函数发生器经功率放大器LM3886TF驱动功率大于90W的扬声器产生超声波,MAX038函数发生器产生的正弦波输出至AT89C52单片机上进行测频,所测频率发送至82C79芯片上供LED显示。这个反馈控制的系统的操作模式可选择不同的刺激频率和刺激时间,从而对不同品种的植物施加最适频率的超声波刺激,以调节植物生长周期和组织器官的生长发育,以及改善次生代谢产物的产生。 相似文献
9.
In order to protect the copyright of digital audio and video in Internet, we propose a novel audio blind watermarking scheme combined discrete wavelets transform, discrete cosine transform, QR decomposition and audio characteristics. In this algorithm, the audio are split into blocks, and each block are decomposed on two dimensional discrete wavelet transform (DWT), then the approximate sub band coefficients are decomposed on discrete cosine transform (DCT), and the first quarter of the DCT coefficients are decomposed on QR decomposition and get a triangle matrix. At last, the watermarking information is embedded into the triangle matrix. The experiments show that the algorithm can get better balance between transparency and robustness of watermark, and it has strong robustness against the common audio signal processing such as additive white Gaussian noise, re sampling, re quantization, low pass filter, MP3 compression and cutting replacement. 相似文献
10.
11.
为明确枣食芽象甲越冬幼虫的空间分布和抽样技术,为该虫预测预报和综合防治提供理论依据,应用8种聚集度指标、Taylor幂法则和Iwao线性回归分析法,对枣食芽象甲越冬幼虫在枣园土壤中的空间分布型和抽样技术进行研究。结果表明：枣食芽象甲越冬幼虫的空间分布呈聚集分布,种群分布的基本成分是个体群,且聚集是由环境因素或者自身的聚集习性引起的;根据Iwao m*-m关系的序贯抽样决策模型确定了枣食芽象甲越冬幼虫的序贯抽样模型和最适理论抽样公式;当枣食芽象甲幼虫防治阈值为30头/株,10株调查枣树虫口密度大于342头,则需采取措施及时进行防治。本研究建立的序贯抽样模型和最适理论抽样公式可用于该象甲越冬幼虫调查、预测预报和综合防治。 相似文献
12.
A method of real time sampling and data processing of ECG signal in Windows98 is introduced in this article. It makes the data collecting and processing easy by driving the A/D transforming card with the Vxd programmed with VtoolsD and VC++, drawing the curve of ECG on memory DC, and utilizing the virtual memory technique to realize the data storing. 相似文献
13.
Optimization design of correction of the control systemby a passive network is studied in this paper.The design method guan-rantees collocation of a closed loop pole in a desired position,but alsominimizes the gain of the system amplifier,thus making the technicalrealization of the system easier.The design method is proved in thepaper. 相似文献
14.
分析奶粉厂可能被阪崎克罗诺杆菌污染的环节,及被检出阪崎克罗诺杆菌的同源性,旨在有效降低奶粉厂阪崎克罗诺杆菌污染风险。利用生理生化法、PCR法和16SrDNA序列分析法分析在配料、生产线、设备及环境收集的微生物样品。共采样25处,其中8处有菌检出,3株鉴定为阪崎克罗诺杆菌。利用16srDNA法对阪崎克罗诺杆菌(ATCC 29544)C.sakazakii E、问题奶粉中的C.sakazakii A、回收细粉中的C.sakazakii H、准备间地漏中的C.sakazakii D四株进行同源性分析,结果表明C.sakazakii A与C.sakazakii H的同源性最高,说明成品中阪崎肠杆菌污染可能源于回收细粉。将8处有菌检出的环节设为关键控制点,其中回收细粉处为最为关键环节,与准备间地漏一同作为阪崎克罗诺杆菌危害关键控制点,本研究对奶粉厂阪崎克罗诺杆菌的控制提供了数据依据。 相似文献
15.
A novel audio steganalysis method is proposed.. the audio signal is denoised with wavelet transform. Then, a part of noise signal with different length is intercepted circularly and is used to calculate the cross correlation sequence with the rest of the noise signal. With the wavelet discontinuity detection technique, the feature is extracted from the cross correlation sequence for steganalysis and find out the steg audio. The detection rate is determined by the embedding strength of the secret message other than the embedding capacity. Experimental results show that the more embedding intensity of PN sequence is, the higher the detection rate will be. The detection rate of the algorithm is above 80% when the strength of the PN sequence is about 0.002, which demonstrates that the proposed algorithm has good detection performance. 相似文献
16.
CHEN Li wan 《保鲜与加工》2001,(1):141-143
The integrated operation amplifier is considered as a central element.When it matches right resistor and capacitor and special connecting methods are adopted,the special resistor,capacitor and inductor are formed.The idea not only expands the range of selection and special requestment to components selection,but also demonstrates special application on integrated operation amplifier and pursues greatly available value on integrated operation amplifier. 相似文献
17.
A balance of maternal and paternal genetic factors, conceptually named the endosperm balance number (EBN), is required for normal endosperm development in interspecific crosses in potato. We previously found that Solanum demissum (D), a hexaploid wild species widely used in potato breeding, has a slightly lower EBN than S. tuberosum (T). To explore the genetic nature of the EBN, the berry-setting rate, seed number/berry, and seed weight were evaluated in BC1 [(D?×?T)?×?T] plants, each possessing different portions of the S. demissum chromosomes, by reciprocal crosses with D and T, and a quantitative trait locus (QTL) analysis was performed. At least 99 S. demissum-derived QTLs were detected, of which 29 were associated with differential responses to D and T. Three QTLs were possibly co-localized on chromosomes 7A and 10D1, while the remaining 23 QTLs were independently located. The QTLs in the three S. demissum homoeologous chromosomes exhibited three types of interaction: (1) positive, (2) negative, and (3) one positive and one negative effect on the same trait. We found that several major genes, one of which was localized in the S. demissum chromosome 9A, and many minor genes controlled the crossability of BC1 plants. The QTLs responsible for the differential responses to D and T were different between the BC1 plants used as male and female parents, indicating that different genes control the male and female EBNs. Consequently, we conclude that the EBN is represented by the sum of various genetic effects controlled by a large number of genes. 相似文献
18.
《保鲜与加工》1998,(2):89-93
A traditional method of experiment on demarcating thermocouple is analyzed and its shortcoming is indicated.It is proposed that the experimental device for demarcating thermocouple should be advanced through application of a microcomputer.The timing for data sampling is carried out in a real time clock way and then the analogue signal is converted into digital information through a A/D converter.Finally, the results of demarcating thermocouple are audio-visually displayed on the screen in a graphic mode. 相似文献
19.
灰飞虱在玉米田空间分布格局及抽样技术研究 总被引：1，自引：1，他引：0
为了提高监测预报与持续控制水平,应用聚集度指标法测定、Iwao法和Taylor幂法则,研究了浙西北玉米田灰飞虱的空间分布格局和抽样技术。结果表明,灰飞虱在玉米田以聚集分布为主,聚集强度随虫口密度增加而增强。其聚集原因经Blackith种群聚集均数测定,当m<1.8072头/株时,其聚集是由某种环境因素（如气候、生育期、长势等）所引起的;当m≥1.8072头/株时,其聚集是由灰飞虱本身生物学特性与环境因素共同作用引起的,在此基础上提出了理论抽样数和序贯抽样模型。研究结果为田间灰飞虱的准确抽样调查和有效防治提供了科学依据。 相似文献
20.
Li Wenyuan Sun Hongbo Zhou Jiaqi 《保鲜与加工》1989,(3):92-98
The paper presents a Monte-carlo method for reliability evaluation of large scale composite generation transmission systems. The method, which possesses coputational rapidity and sufficient accuracy,is based on combining the dispersed sampling techique with the analysis approach and the optimization model of power not supplied. Because the amount of calculation increases only linearly with, the number of elements, it is specially sui-
table for large scale systems. The Monte-carlo sampling draws more near the
real situation than determinate state enumeration in simulating occurrence of power system outages. Also, the method can be easily generalized to involve multi-states of elements, multi-levels and stochastic distribution of loads. The results of IEEE-RTS, as example, are given and compared with ones obtained by using the other two methods. 相似文献