The English name is NoteBook, commonly known as notebook computer. Portable, notebook computer, NB for short, also known as laptop or notebook computer (Hong Kong and Taiwan call it notebook computer 1), is a small, portable personal computer, usually weighing 1-3 kg. Its development trend is smaller and lighter, but stronger. Like a netbook, also known as a netbook, the main difference from a PC is that it is easy to carry.
Major brands and manufacturers of ASUS notebook computers
Hp notebook computer
Dell notebook computer
Toshiba notebook
Sony notebook
Acer notebook
Shenzhou notebook
BENQ (benq) notebook
Samsung notebook
thinkpad
Apple notebook
What is the main frequency of computer cpu? Is the higher the main frequency of cpu, the better? (1) When discussing computer hardware, we often mention the word "main frequency of computer cpu", but what is the main frequency of computer cpu? I believe many novice friends don't understand it very well. Let's get to know it together!
In electronic technology, pulse signal is a continuous pulse signal with a certain voltage amplitude and a certain time interval. The time interval between pulse signals is called period; The number of pulses generated per unit time (such as 1 sec) is called frequency.
The so-called frequency is a measurement name that describes the number of pulses that appear in a unit time for periodic cyclic signals (including pulse signals); The standard unit of measurement of frequency is hertz. The system clock in the computer is a typical pulse signal generator, and its frequency is quite accurate and stable.
Frequency is represented by "f" in mathematical expression, and the corresponding units are: hertz (Hz), kilohertz (kHz), megahertz (MHz) and gigahertz (GHz). Where 1GHz= 1000MHz, 1MHz= 1000kHz, 1kHz= 1000Hz. Calculate the time unit of the pulse signal period and the corresponding conversion relationship: s (seconds), ms (milliseconds), μs (microseconds) and ns (nanoseconds), where: 1s= 1000ms, 1ms = 1000ms,.
The main frequency of computer CPU indicates the oscillation speed of digital pulse signal in CPU, which is not directly related to the actual computing power of CPU. There is a certain relationship between the main frequency and the actual running speed, but there is no definite formula to quantify the numerical relationship between them, because the running speed of CPU depends on the performance indicators of CPU pipeline (cache, instruction set, CPU bits, etc.). ).
Because the main frequency of computer CPU does not directly represent the running speed, in some cases, it is likely that the CPU with higher main frequency will actually run at a lower speed. For example, most of AMD's AthlonXP series CPU can achieve the CPU performance of Intel's Pentium 4 series CPU at a low frequency, so AthlonXP series CPU is named after PR value. Therefore, the main frequency is only one aspect of CPU performance, not the overall performance of CPU, which should be paid attention to when installing our computer.
The main frequency of computer CPU does not represent the speed of CPU, but improving the main frequency is very important to improve the running speed of CPU.
Assuming that a CPU executes an operation instruction in a clock cycle, when the CPU runs at 100MHz, it will be twice as fast as when it runs at 50MHz. Because the clock cycle of 100MHz is half of that of 50MHz, that is, the CPU working at 100MHz only needs 10ns to execute an operation instruction, which is half of that of 20ns working at 50MHz, and the natural operation speed is doubled. However, the overall running speed of the computer depends not only on the running speed of the CPU, but also on the running speed of other subsystems. Only when the main frequency is improved, the running speed of each subsystem and the data transmission speed between subsystems can be improved, and the overall running speed of the computer can be really improved.
Since CPU is made on a semiconductor silicon wafer, the components on the silicon wafer need to be connected by wires. Because the wire is required to be as thin as possible at high frequency, it can reduce stray interference such as distributed capacitance of the wire and ensure the correct operation of CPU. Therefore, the limitation of manufacturing process is one of the biggest obstacles to the development of CPU main frequency. Therefore, improving the working frequency of CPU is mainly limited by the production process.
What is the main frequency of computer cpu? That is, the CPU clock speed at which the CPU core works. How many megahertz is a certain CPU? This megahertz is the "CPU main frequency". Many people think that the main frequency of CPU is its running speed, but it is not.
Is the cpu frequency as high as possible? This is not necessarily because the main frequency is only one aspect of CPU performance and does not represent the overall performance of CPU. There are also external frequency, FSB frequency, memory and so on. If they don't match well, it's like a expressway. When it is wide, it is very popular with everyone. When it is narrow, there will be traffic jams, and all the data will be stuck there, which is what people call a bottleneck. In a big bottle, it will be poured out bit by bit through a narrow bottle mouth, so it is necessary to reasonably match all the hardware. & ampn
bsp
For example, most of AMD's AthlonXP series CPU can achieve the CPU performance of Intel's Pentium 4 series CPU at a low frequency, so AthlonXP series CPU is named after PR value. Therefore, the main frequency is only one aspect of CPU performance and does not represent the overall performance of CPU. The main frequency of CPU does not represent the speed of CPU, but increasing the main frequency can improve the operation of CPU.
What is the power supply circuit? The power supply circuit is an important part of the motherboard. Its function is to convert the current from the host power supply to voltage, convert the voltage into the core voltage acceptable to the CPU, and make the CPU work normally, and shape and filter the current from the host power supply to filter out all kinds of clutter and interference signals, so as to ensure the stable operation of the computer. The main part of the power supply circuit is generally located near the CPU slot of the motherboard.
Linear power supply mode
This is the main board power supply mode many years ago, which is realized by changing the conduction degree of the transistor. The transistor is equivalent to a variable resistor and is connected in series in the power supply circuit. Because the variable resistor flows through the same current as the load, it consumes a lot of energy, which leads to the temperature rise and the voltage conversion efficiency is low. Especially in the power supply circuit that needs large current, linear power supply cannot be used. At present, this power supply mode has long been eliminated.
Switching power supply mode
This is a widely used power supply method at present. The PWM controller IC chip provides pulse width modulation and sends out pulse signals to turn on MOSFET 1 and MOSFET2 in turn. Chokes L0 and L 1 are used as energy storage inductors, and together with the connected capacitors, an LC filter circuit is formed.
Its working principle is: when the voltage at both ends of the load (such as the voltage required by CPU) is to be reduced, the external power supply charges the inductor through the switching action of MOSFET to reach the required rated voltage. When the voltage across the load rises, the external power supply is disconnected through the switching effect of MOSFET, and the inductor releases the energy just charged, and then the inductor becomes the power supply to continue to supply power to the load. With the consumption of energy stored in the inductor, the voltage across the load begins to decrease gradually, so it is necessary to charge the external power supply through the switching effect of MOSFET. By analogy, in the process of continuous charging and discharging, it will become a stable voltage and will never increase or decrease the voltage at both ends of the load. This is the biggest advantage of switching power supply. In addition, because the MOSFET works in the switching state, its internal resistance when turned on and leakage current when turned off are very small, so its own power consumption is very small, which avoids the problem that the resistor part of the linear power supply in series in the circuit consumes a lot of energy. This is also the working principle of the so-called "single-phase power supply circuit".
Generally, a single-phase power supply can provide a maximum current of 25A, but the commonly used CPU has already exceeded this figure. The power of P4 processor can reach 70-80W, and the working current even reaches 50A. Single-phase power supply can not provide enough reliable power, so now the power supply circuit design of motherboard adopts two-phase or even multi-phase design. It is a schematic diagram of two-phase power supply, which is easy to understand. It is a parallel connection of two single-phase circuits, so it can provide double current supply, which is more than enough to meet the current CPU demand in theory. But the above is only pure theory, and many practical factors need to be added, such as the performance of switching elements and the resistance of conductors, which are all factors that affect Vcore. In practical application, there are efficiency problems in the power supply, and the electric energy will not be converted into 100%. Generally speaking, the consumed electric energy will be converted into heat and emitted, so any common regulated power supply is the part with higher temperature in electrical components. It should be noted that the higher the temperature, the lower its efficiency. In this way, if the conversion efficiency of the circuit is not very high, then the circuit using two-phase power supply may not meet the needs of CPU, so there are three-phase or even more power supply circuits. However, it also brings the complexity of motherboard wiring. If the wiring design is unreasonable at this time, it will affect the stability of high frequency work and a series of problems will appear. At present, many mainstream motherboard products in the market use three-phase power supply circuit, which can provide enough power for CPU. However, due to the lack of circuit design, the stability of the motherboard is limited to some extent in extreme cases. If we want to solve this problem, we must make greater efforts in circuit design and wiring, and the cost will rise.
The reason why the power supply circuit adopts multiphase power supply is to provide more stable current. The pulse square wave signal sent from the control chip PWM is shaped into a DC-like current through the LC oscillating circuit. The high potential time of square wave is very short. The more phases, the closer the quasi-DC is to DC.
The power supply circuit plays a very important role in the performance and stability of the computer, and is an important performance parameter of the motherboard. When purchasing, you should choose products with excellent design and sufficient materials from mainstream manufacturers.
What does cdkey mean? How to collect CDKEY? CDKEY refers to the serial number required for software registration. Most commercial software needs to install serial number (or CDKEY code), which is usually marked on the product packaging or manual. The installation serial number (SN, serial number) and CDKEY code form a specific product registration code after software installation. Users can also use this registration code to register with software vendors to obtain various technical support services in the future.
CDKEY only refers to the serial number required for software registration.
CD, key, key. This is the key to the CD. The technical term is registration code, which is actually a password. But the difference between this password and ordinary password is that it can only be entered by reading the disk, not from the keyboard, even if others know it. General online banking needs it to ensure the security of customer information.
Simply put, cd key is a software registration code.
Password or serial number of the software installed on the CD.
For example, the system installation CD has a long row of boxes for you to enter the number when installing the system.
According to the name, you should know something. A CD is a kind of optical disc. KEY means key, which is the key to open the CD. The popular answer is the registration code or serial number!
The technical term is registration code, which is the registration code and key of software.
What does ghz mean? What does computer ghz mean? abstract
The unit of frequency is Hz, abbreviated as Hz, and represented by the symbol "Hz". Commonly used frequency units are kilohertz (KHz), megahertz (MHz), gigahertz (GHz) and so on. Hertz is a famous German physicist. 1887, he confirmed the existence of electromagnetic waves through experiments. In order to commemorate him, later generations set "Hertz" as the frequency unit.
physics
GHz, abbreviated as "GHz", is the frequency unit of alternating current or electromagnetic wave, which is equal to one billion hertz (1 0,000,000,000 Hz). Gigahertz is the frequency indication unit of ultra-high frequency (UHF) and microwave signals. The wavelength of electromagnetic wave signal with frequency of 1GHz is 300mm, which is shorter than one foot. The wavelength of electromagnetic wave signal with frequency of 100GHz is 3 mm, which is about 1/8 inches. Some radio broadcasts use frequencies above several hundred GHz. Other commonly used frequency units are kHz, which is equivalent to 1 0,0000 Hz or 0.00000100 Hz; Megahertz, equivalent to 1, 000,000 Hz or 0.00 100 Hz.
computer
Gigahertz is one billion hertz (65438+10 9 hertz 1 000 000 000 hertz). GHz is the processing frequency of CPU, in other words, the processing speed of CPU. Now most CPUs are multi-core, such as dual-core, 4-core, 8-core, 16-core, etc. If so, the actual frequency of the CPU is equal to the main frequency multiplied by the core value and then multiplied by about 0.8. For example, a 4-core 1.5GHz CPU has an actual processing speed of 4X 1.5X0.8=4.8(GHz). The larger the value, the faster the CPU runs and the stronger the performance. In addition, it is also used to observe the clock frequency of the microprocessor. Memory is now mainly in MHz.
Understanding and sharing of netizens:
Frequency units commonly used in computers.
1GHz= 1000MHz
1MHz= 1000kHz
1 kHz = 1000 Hz
1000Hz means 1000 times per unit time (one second).
In computers, cpu frequency is used for a long time. Now the cpu frequency is 2~4GHz.
There is also the frequency of the bus, which is generally MHz. For example, the working frequency of DDR2 memory is 800MHz.
GHZ stands for G Hz, and g is a unit, 1G= 1024M, 1M= 1024K. 1K is equal to 1024 bytes. 1 byte =8 bits, which is the conversion of computer!
What does UWB mean? (1) UWB technology is a new type of wireless communication technology. By directly modulating pulses with steep rise and fall times, the signal has a bandwidth of GHz. Ultra-wideband (UWB) technology has solved the main propagation problems that have plagued traditional wireless technology for many years. It has the advantages of insensitivity to channel fading, low power spectral density of transmitted signal, low interception ability, low system complexity and positioning accuracy of several centimeters.
Advantages of ultra-wideband
Compared with other wireless communication technologies, UWB has many advantages. Table 1 compares UWB technology with other wireless LAN technologies. Ultra-wideband technology is characterized by high transmission rate, large system capacity, strong anti-multipath ability, low power consumption and low cost. UWB transmits information by changing the amplitude, interval or duration of pulses. Compared with narrowband transceiver and Bluetooth transceiver, UWB does not need to generate sinusoidal carrier signal, and can directly transmit impulse pulse sequence, so it has wide spectrum and low average power, which is beneficial to storage with other systems and improves spectrum utilization.
UWB does not need sine wave modulation, up-conversion and down-conversion, nor does it need local oscillator, power amplifier and mixer, so it is small in size and simple in system structure. UWB signal processing is relatively simple, only a few RF or microwave devices are needed, the RF design is simple, and the frequency adaptability of the system is strong. The front-end of pulse transmitter and receiver can be integrated on a chip, and together with time base and controller, it constitutes an ultra-wideband communication device. Therefore, its cost can be greatly reduced.
Because UWB signal adopts time-hopping spread spectrum, its RF bandwidth can reach more than 1GHz, and its transmission power spectral density is very low. The signal is hidden in environmental noise and other signals and cannot be received and recognized by traditional receivers. It is necessary to use the spread spectrum code pulse sequence consistent with the transmitter for demodulation, thus increasing the security of the system.
Ultra-wideband signal has low fading and strong anti-multipath fading ability. The high bandwidth of UWB signals brings huge system capacity. Because of the ultra-wideband radio signal's extremely low pulse duty cycle, high system gain and strong multipath resolution, the system capacity is higher than other wireless technologies.
Because the spread spectrum processing gain of UWB signal is relatively large, even if the omnidirectional antenna with low gain is used, the transmission power less than 1mW can be used to realize communication for several kilometers. Such a low transmission power prolongs the service time of the system power supply, which is very suitable for the application of mobile communication equipment. The research shows that the standby time of mobile phone using ultra-wideband can reach 6 months, and the harm of excessive electromagnetic radiation to human body can be avoided with low radiation power.
Application of ultra-wideband RT
With the commercialization of UWB-RT, it is possible to deploy short-range wireless communication systems that support high-speed applications and low-speed intelligent devices. The UWB antenna system defined by FCC adopts a simple modulation and coding mechanism, and the information rate that can be achieved in a short distance is greater than 100Mb/s/s, so UWB can compromise between information rate and coverage.
A large number of application scenarios are suitable for UWB, including: high-speed wireless personal network (HDR-WPAN); Wireless Ethernet interface link (Weil); Smart antenna area network (iwan); Outdoor point-to-point network (OPPN); Sensor, Positioning and Identification Network (SPIN).
The first three cases assume that the UWB equipment network is deployed in residential areas or office areas, and mainly transmits wireless video/audio and control signals for entertainment. The fourth case provides outdoor point-to-point connection, while the fifth case considers industrial and commercial environment.
1. High-speed wireless personal network (HDR-WPAN)
HDR-WPAN is defined as: the number of active devices in each room is 5 ~ 10, and the data rate is 1 ~ 10m, which is mainly based on peer-to-peer topology. Use existing wired or wireless standards to connect with the outside world through relay.
2. Wireless Ethernet Interface Link (WEIL)
The concept of HDR can be extended to higher data rates, such as 1Gb/s and 2.5 GB/S. Weil, to meet the following requirements: from the perspective of PC manufacturers, substitutes for Ethernet cables are needed; From the consumer's point of view, high-quality wireless video transmission capability is needed between PC and LCD screen, which can transmit wireless digital video.
3. Smart Antenna Area Network (IWAN)
IWAN is characterized by covering 30m indoor or high-density equipment offices. The requirements for equipment are: low cost,
Low power consumption, such as 1 ~ 10MW, provides users with home/office intelligent distribution network. The functions of equipment include: accurate positioning, tracking and supporting environmentally sensitive equipment, which is not easy to realize in the current narrow-band short-distance network. In this case, the last mile of wireless or available connection with the outside world can be used to send alarms, control signals or remotely check the status of sensors in the home.
4. Outdoor Peer-to-Peer Network (OPPN)
UWB equipment is deployed outdoors, which is mainly suitable for PDA uplink and information exchange, news text, pictures and video download. Which standard will determine whether OPPN structure is centralized or distributed is a subject that needs further study.
The UWB standard to be adopted in Europe will strictly limit the deployment of outdoor UWB equipment. However, this situation may change because the use of UWB supervision will continue to improve, just as other wireless services have experienced in the past.
5. Sensor, Positioning and Identification Network (SPIN)
SPIN system is characterized by high equipment density, several hundred per floor, mainly in factories or warehouses, sending low-speed data packets with positioning information. Spinning equipment is widely used. If it is a master-slave topology, 100m can be achieved between a single device and the master station. In industrial applications, SPIN needs advanced link reliability and adaptive system characteristics to respond to the dynamically changing interface and propagation environment.
Ultra-wideband will play an important role in providing effective services according to users' needs. The division of scene mechanism and the development of various networks, including the various situations analyzed above, are far from the expectations of users. A grand goal is to realize seamless storage and interoperability of various networks in different scenarios. Therefore, designing effective connection, automatic roaming mechanism and data link adaptation is an important research topic in the future.