Instruct: Given a question, retrieve relevant documents that can help answer the question.
Query: Is analog or digital more reliable?
Digital electronics or digital (electronic) circuits are electronics that operate on digital signals. In contrast, analog circuits manipulate analog signals whose performance is more subject to manufacturing tolerance, signal attenuation and noise. Digital techniques are helpful because it is a lot easier to get an electronic device to switch into one of a number of known states than to accurately reproduce a continuous range of values.
SDDS was consistently the least popular of the three competing digital sound formats, the other two being Spectral Recording Dolby Stereo Digital and DTS. Along with being the most expensive to install (and the last to arrive), there were major reliability issues with SDDS. Due to the change from the prototype placement to the very edges of the film stock, SDDS tracks are prone to damage as are some other digital formats. As with other digital sound formats: any failure of the digital track could result in a "drop-out" of the digital format and possibly a switch to analog sound. Additionally a drop-out resulting in a switch to Analog (Analogue) may produce a slight loss of fidelity and high and low-ends, similar to a "CD skipping", although it is more difficult to tell in a properly calibrated auditorium.
The push for reduced cost, more compact circuit boards, and added customer features has provided
incentives for the inclusion of analog functions on primarily digital MOS integrated circuits (ICs) forming
mixed-signal ICs. In these systems, the speed of digital circuits is constantly increasing, chips are
becoming more densely packed, interconnect layers are added, and analog resolution is increased. In addition, recent increase in wireless applications and its growing market are introducing a new set of aggressive design goals for realizing mixed-signal systems. 
Here, the designer integrates radio frequency
(RF) analog and base band digital circuitry on a single chip. 
The goal is to make single-chip radio frequency
integrated circuits (RFICs) on silicon, where all the blocks are fabricated on the same chip. 
One of the advantages of this integration is low power dissipation for portability due to a reduction in the number of package pins and associated bond wire capacitance. 
Another reason that an integrated solution offers lower power consumption is that routing high-frequency signals off-chip often requires a 50Ω impedance match, which can result in higher power dissipation. 
Other advantages include improved high-frequency performance due to reduced package interconnect parasitics, higher system reliability, smaller package count, and higher integration of RF components with VLSI-compatible digital circuits. 
In fact, the single-chip transceiver is now a reality.
However, on later operating systems the digital mode would be less and less reliable, and on modern PCs most 3D Pro owners can only run in analog mode. The 3D Pro was popular enough to spawn a successor, the Precision Pro, which was a USB device and, while it did not work in DOS at all, was far more reliable under Windows despite quality issues.
Hybrid computers should be distinguished from hybrid systems. The latter may be no more than a digital computer equipped with an analog-to-digital converter at the input and/or a digital-to-analog converter at the output, to convert analog signals for ordinary digital signal processing, "and conversely", e.g., for driving physical control systems, such as servomechanisms.
Since digital circuits are made from analog components, digital circuits calculate more slowly than low-precision analog circuits that use a similar amount of space and power. However, the digital circuit will calculate more repeatably, because of its high noise immunity. On the other hand, in the high-precision domain (for example, where 14 or more bits of precision are needed), analog circuits require much more power and area than digital equivalents.
AN/AWG-10A is a development of the original AN/AWG-10, with great improvement in reliability and maintainability by replacing the original transmitter in AN/AWG-10 by a solid state unit whose only tube was a klystron power amplifier. Adding a digital computer allowed much more effective missile launch equations. AN/AWG-10A also incorporated a new servoed optical sight. There were also additions of new modes such as continuously displayed impact point mode, freeze displayed impact mode, and computer released visual mode. AN/AWG-10B was further digitized version of AN/AWG-10/10A but retained many analog circuits. A key AVC (avionics change) was the replacement of the unreliable Doppler Spectrum Analyzer (DSA) with a reliable Digital Spectrum Processor (DSP) which also increased accuracy when operating in doppler mode.
This work suffered from the reliability of the analog circuits used to run the system. By the early 1950s the digital computer appeared to offer a solution, not only by greatly increasing reliability through the removal of any moving parts, but also by directly working with the digital data that made up the plots. Data from one computer simply needed to be copied directly to another, there was no need to code and decode analog signals representing those values. The Royal Canadian Navy began work on such a system under their DATAR project, which included the first working example of the trackball concept. Unfortunately their design used tubes, and the resulting machine was so large it took up almost all of the free space on the it was installed on. Efforts to build a transistorized version of the DATAR did not receive funding and the project ended.
This method of synthesis is also referred to as Virtual Analog or VA. Analog modeling synthesizers can be more reliable than their true analog counterparts since the oscillator pitch is ultimately maintained by a digital clock, and the digital hardware is typically less susceptible to temperature changes.
WHYY-TV's digital signal initially operated at so low a power that even those who lived in some areas of the city of Philadelphia could not receive it reliably. The station shut down its analog signal, over VHF channel 12, on June 12, 2009, the official date in which full-power television stations in the United States transitioned from analog to digital broadcasts under federal mandate. The station's digital signal relocated from its pre-transition UHF channel 55 to VHF channel 12 for post-transition operations.
Data converters include analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) that convert electrical signal representations of real-world analog phenomena, such as light, sound, waveforms, temperature, motion, and pressure into digital signals or data, and back again. Analog Devices ADC and DAC ICs are used in medical systems, scientific instrumentation, wireless and wired communications, radar, industrial process control, audio and video equipment, and other digital-processing-based systems, where an accurate signal conversion is critical. Data converters account for more than 50% of ADI's revenue. ADI's companion amplifier ICs provide accurate, high-speed and precise signals for driving data converters and are key for applications such as digital audio, current sensing, and precision instrumentation.
Digital television (DTV) is the transmission of television signals, including the sound channel, using digital encoding, in contrast to the earlier television technology, analog television, in which the video and audio are carried by analog signals. It is an innovative advance that represents the first significant evolution in television technology since color television in the 1950s. Digital TV transmits in a new image format called HDTV (high definition television), with greater resolution than analog TV, in a wide screen aspect ratio similar to recent movies in contrast to the narrower screen of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit multiple channels, up to 7, in the same bandwidth occupied by a single channel of analog television, and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2006 in some countries, and many industrial countries have now completed the changeover, while other countries are in various stages of adaptation. Different digital television broadcasting standards have been adopted in different parts of the world; below are the more widely used standards:
During the analog to digital transition that occurred during the life-span of SyntheSys Research, many techniques were employed by engineers to evaluate digital transmission. Analog transmission had been characterized by modestly simple measurements of the analog waveform such as rise-time, signal-to-noise ratio and frequency response. Digital transmission, however, employed sophisticated coding and error correction and other mechanisms that could perfectly recreate digital bits even if the underlying analog waveform was quite bad, and made it much more difficult to have a single qualitative figure of merit for the performance of the digital transmission. BER was a very useful measure, but it didn't degrade politely like analog signal-to-noise measurements. In digital communications, a "cliff-effect" occurs which means communication is often perfect until it fails completely.
Analog chips may also contain digital logic elements to replace some analog functions, or to allow the chip to communicate with a microprocessor. For this reason and since logic is commonly implemented using CMOS technology, these chips use BiCMOS processes by companies such as Freescale, Texas Instruments, STMicroelectronics and others. This is known as mixed signal processing and allows a designer to incorporate more functions in the chip. Some of the benefits include load protection, reduced parts count and higher reliability.
The main difference is that a digital synthesizer uses digital processors and analog synthesizers use analog circuitry. A digital synthesizer is in essence a computer with (often) a piano-keyboard and an LCD as an interface. An analog synthesizer is made up of sound-generating circuitry and modulators. Because computer technology is rapidly advancing, it is often possible to offer more features in a digital synthesizer than in an analog synthesizer at a given price. However, both technologies have their own merit. Some forms of synthesis, such as, for instance, sampling and additive synthesis are not feasible in analog synthesizers, while on the other hand, many musicians prefer the character of analog synthesizers over their digital equivalent.
Two prominent differences in performance between the two methods are the bandwidth and the signal-to-noise ratio (S/N). The bandwidth of the digital system is determined, according to the Nyquist frequency, by the sample rate used. The bandwidth of an analog system is dependent on the physical capabilities of the analog circuits. The S/N of a digital system may be limited by the bit depth of the digitization process, but the electronic implementation of conversion circuits introduces additional noise. In an analog system, other natural analog noise sources exist, such as flicker noise and imperfections in the recording medium. Other performance differences are specific to the systems under comparison, such as the ability for more transparent filtering algorithms in digital systems and the harmonic saturation and speed variations of analog systems.
An analog computer or analogue computer is a type of computer that uses the continuously changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities symbolically, as their numerical values change. As an analog computer does not use discrete values, but rather continuous values, processes cannot be reliably repeated with exact equivalence, as they can with Turing machines. Unlike machines used for digital signal processing, analog computers do not suffer from the discrete error caused by quantization noise. Instead, results from analog computers are subject to continuous error caused by electronic noise.
In the early 1970s analog computer manufacturers tried to tie together their analog computer with a digital computer to get the advantages of the two techniques. In such systems, the digital computer controlled the analog computer, providing initial set-up, initiating multiple analog runs, and automatically feeding and collecting data. The digital computer may also participate to the calculation itself using analog-to-digital and digital-to-analog converters.
In most cases the functions performed by an analog multiplier may be performed better and at lower cost using Digital Signal Processing techniques. At low frequencies a digital solution is cheaper and more effective, and allows the circuit function to be modified in firmware. As frequencies rise, the cost of implementing digital solutions increases much more steeply than for analog solutions. As digital technology advances, the use of analog multipliers tends to be ever more marginalised towards higher-frequency circuits or very specialized applications.
IC design can be divided into the broad categories of digital and analog IC design. Digital IC design is to produce components such as microprocessors, FPGAs, memories (RAM, ROM, and flash) and digital ASICs. Digital design focuses on logical correctness, maximizing circuit density, and placing circuits so that clock and timing signals are routed efficiently. Analog IC design also has specializations in power IC design and RF IC design. Analog IC design is used in the design of op-amps, linear regulators, phase locked loops, oscillators and active filters. Analog design is more concerned with the physics of the semiconductor devices such as gain, matching, power dissipation, and resistance. Fidelity of analog signal amplification and filtering is usually critical and as a result, analog ICs use larger area active devices than digital designs and are usually less dense in circuitry.
Analog computing devices are fast, digital computing devices are more versatile and accurate, so the idea is to combine the two processes for the best efficiency. An example of such hybrid elementary device is the hybrid multiplier where one input is an analog signal, the other input is a digital signal and the output is analog. It acts as an analog potentiometer upgradable digitally. This kind of hybrid technique is mainly used for fast dedicated real time computation when computing time is very critical as signal processing for radars and generally for controllers in embedded systems.
Digital filters may be more expensive than an equivalent analog filter due to their increased complexity, but they make practical many designs that are impractical or impossible as analog filters. Digital filters can often be made very high order, and are often finite impulse response filters which allows for linear phase response. When used in the context of real-time analog systems, digital filters sometimes have problematic latency (the difference in time between the input and the response) due to the associated analog-to-digital and digital-to-analog conversions and anti-aliasing filters, or due to other delays in their implementation.
On cable television systems, analog-digital simulcasting (ADS) means that analog channels are duplicated as digital subchannels. Digital tuners are programmed to use the digital subchannel instead of the analog. This allows for smaller, cheaper cable boxes by eliminating the analog tuner and some analog circuitry. On DVRs, it eliminates the need for an MPEG encoder to convert the analog signal to digital for recording. The primary advantage is the elimination of interference, and as analog channels are dropped, the ability to put 10 or more SDTV (or two HDTV, or various other combinations) channels in its place. The primary drawback is the common problem of over-compression (quantity over quality) resulting in fuzzy pictures and pixelation.
Nowadays, the growing pace of innovations in electronics drives to new solutions for energy and information transfer to enhance its speed, efficiency and reliability. For most devices, this solution is a transition from analog to digital. Possibly the most prominent example of such conversion is the modern digital computer. But the wires in all digital systems still remain analog. Digital wire becomes indispensable for providing efficient, robust, adaptable, and cost effective energy supply. Presently, no one knows, however, how it is supposed to work or what technology would be able to create such a device.
Personal locator beacons operating on 406 MHz must be registered. PLBs should not be used in cases where normal emergency response (such as 9-1-1) exists.The most important aspect of a beacon in classification is the mode of transmission. There are two valid transmission modes: digital and analog. Where digital usually has a longer range, analog is more reliable. Analog beacons are useful to search parties and SAR aircraft, though they are no longer monitored by satellite.