浅谈数字录音技术音频信号的数字化

主要介绍数字录音技术中的两个方面，即音频信号的数字化和磁光式数字录音机。     

谈谈录音的方法

使用录音机录音的方法很多,使用机内话筒及外接话筒录音很容易,但利用其它方式录音就比较复杂,因要考虑信号源的输出和录音机的输入相匹配,才能获得良好的录音效果,否则连接不当将造成录音信号严重失真。输出和输入的匹配条件是:信号源的输出阻抗要低于录音机的输入阻抗,输出电平要大约等于录音机的输入电平。在录音的时候除了掌握一些其他注意事     

数字录音的电平控制

解释了数字设备的过载显示器、数字电平表的基本原理,并解释数字录音与响度的关系。同时还介绍了涉及数字声音后期制作工作中电平校准方法,特别是数字与模拟设备混合系统的校准方法。     

数字光盘录音

讨论了可录CD和可录MD的数字光盘录音原理，叙述了CD—R，MD—RW(MD—MO)，CD—RW(CD—MO)光盘和相应的光盘录音机。     

智能型数字录音电话机

本刊1995年12期刊出“智能电话机”一文后,收到很多读者来信,要求详细介绍此类电话机的特点和使用方法。现请王伟同志撰写此文,以HL946P/T为例叙述智能型电话机的新功能及使用方法。     

全固态录音技术

全固态录音技术电子部科技情报所胡朝阳１概述从１８９８年丹麦波尔逊发明钢丝录音机算起，录音技术问世已有近百年历史，不过从盒式磁带录音机问世算起，也只有３０多年历史。在此３０多年里，尤其是近１０余年里，录音技术发展日益增快。其中最引人注目的是数字式录音技...     

数字混响器在录音工艺中的应用

本文以Lexicon 224XL数字混响/效果为例,从调整混响及效果的几个重要参数的基本概念出发,对在录音创作过程中如何合理地选择预置程序,如何正确地设置参数值提出了一些看法,并介绍了几种典型节目的混响及效果的制作方法。     

数字音频记录媒体的发展和比较

国际上音频数字化的浪潮此起彼伏，我国的音频工作者和音频设备制造者应如何面对这种形势。本文通过对数字音频记录媒体发展的回顾和几种流行的数字记录媒体的比较，阐明作者的见解。     

模拟电吉他效果器与数字电吉他效果器对比实验

分析了电吉他效果器发展至今延伸出模拟与数字两种规格的产品原理和特点。继而论述了不同原理的设备在效果上的异同,并提出了量化分析这种异同的设想,对实际运用的选择以作参考。Roland公司旗下有名为Boss的模拟效果器系列,并有对应的数字综合效果器系列。因此,可借此为分析对象,控制变量,设计了实验:生产由相同吉他信号通过其产生的不同音色样本,并对样本进行包络、频谱等研究,分析其音色属性。最后搭建了系统完成了实验,得到了相关的数据。最终,经分析数据得出:OD-1相比ME-25灵敏度更低;高次谐波上激励更强,音色更为明亮;产生的高频噪声成分更单纯,声音更干净;对于电吉他的琴体振动反应更为敏锐,产生的噪声更为复杂。     

Analog Data Recording with a Video Cassette Recorder

A multichannel, analog data storage system is presented which utilizes a compact video cassette recorder. Typical video cassette recorders operate at 3?ips and consequently allow up to one hour of continuous recording. The rotary two-head, helical-scan system employed yields a relative head-to-tape speed of 404.3 ips and a bandwidth of 3 to 4 MHz. The analog recording system described herein consists of an encoder which multiplexes and digitizes eight analog signals, a video recorder for storage of the digital data, and a decoder which demultiplexes and recovers the analog information. One unique feature of this system is that digital words which are generated consist of the channel number as well as the analog information present on that channel at the time of sampling. All information is combined serially and recorded with each word uniquely separated by a special "sync pulse." Another system feature is the ability to individually select the data bandwidth of each analog channel from values between approximately 25 kHz to 3 Hz. Design, fabrication, and evaluation is given. Interfacing to computing systems and microprocessors is discussed. An eight channel system with eight bit data words is described yielding approximately one-half percent resolution. However, the system is readily expandable to any number of channels and up to 16 bit data words yielding more resolution or higher signal-to-noise ratio.     

数字与模拟集成电路发展趋势

随着数字技术的迅猛发展,在半导体工艺、平版印刷、金属化和封装等技术进步的支持下,比以往更快、更复杂的数字电路正在成为现实。运算速度高达3GHz、集成了近1亿个晶体管的64位微处理器即为一例。有些DSP可提供数千兆浮点运算的存吐量。动态随机存取存储器(DRAM)已达到512MB的容量和每个I/O引脚上666Mbps的数据传输速率。快闪存储器的容量达到了1～2GB。某些ASIC所具有的门电路的数量超过了一千万,而FPGA目前则宣称具有三百万个门电路和数GHz的I/O端口。     

磁带记录与时序器记录的比较

本文对磁带录音（磁带演播室）和时序器录音（无磁带演播室）这两种录音方式进行了比较，从中可以了解到这两种录音方式的优缺点。     

Digital Applications of Thermoplastic Recording

Thermoplastic films' unique combination of thermal, electrical, and optical properties results in a versatile information storage medium which finds both digital and analog applications. As a digital storage medium, thermoplastic is best suited as a file memory where large capacity and rapid read access is a necessity. Reading and writing rates are completely independent. The fabrication of either sequential or random access devices using tapes or plates is possible. These couple high density capability with electron beam agility to provide large capacity storage and outstanding performance with regards to data transfer rates and read access. The recording medium consists of a substrate for mechanical carriage, a conductive film for heat developing, and the thermoplastic film. The recording process consists of writing line charges with a data-modulated electron beam and then developing with heat. The surface grooves which are formed can be read optically with a flying spot scanner. The position feedback Information inherent in the recorded data allows tracking along a single groove regardless of density.     

Combined Analog and Digital Error-Correcting Codes for Analog Information Sources

This paper focuses on error-correcting codes for analog signals. Generally, error-correcting codes exhibit a threshold effect, which degrades performance at the low signal-to-noise ratio (SNR) range. We propose two error-correction alternatives based on chaotic dynamical systems, which improve threshold performance relative to previously proposed methods. The first one, which is based on principles of diversity, exhibits a very simple decoder. The second alternative, which is based on a low-density parity-check (LDPC) code, attains a significantly lower threshold. Theoretical analysis and simulations are provided.     

模拟微波的数字化改造

主要阐述模拟微波的数字化改造的必要性和优点,提出具体的数字微波收发信方案,论述了模拟微波数字化改造是无线数字电视可行的一种重要传输方式。     

数字和模拟微波混合传输的研究与实现

随着微波数字化的进程,传统的微波站已无法满足日益增长的传输业务。研究发现,利用早期的模拟微波传输通道来同时传输模拟和数字微波信号,是一种可行的解决办法。文章以湖北省西南干线微波系统改造为例,提出了数字和模拟微波混合传输系统的改造方法及相关的关键问题。     

广播影视业中的数字录音

１概述数字录音的记录方式有两种：一是以磁带为记录载体的顺序记录方式如ＤＡＳＨ、ＰＤ、ＤＣＣ、ＤＡＴ等。二是以盘片如软盘、光盘、硬盘为记录载体的随机记录方式如ＣＤ、ＭＤ、ＨＤ、ＭＯ等，这种记录也叫无磁带化记录。这里重点阐述数字磁带录音与数字音频工作站录音这两种数字录音方式的功能与特点。２数字磁带录音机大家知道磁带录音机对声频信号的处理一直是采用模拟式。信号的处理只是各种能量形式的转换或辐度的增减。信号各点之间的关系是不变的。这统称为模拟式磁带录音机。模拟磁带录音机的频率响应，动态范围比较差，磁带的…