The PCI Express [PCIe] bus defines the Electrical, topology and protocol for the physical layer of a point to point serial interface over copper wire or optical fiber. In addition to the Physical Layer, the PCI Express specification also covers the Transaction Layer and Data Link Layer. The Physical Layer resides with Layer 1, and the Data Link La
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yer resides with Layer 2 of the OSI protocol model. PCI Express is the new serial bus addition to the PCI series of specifications. How ever the electrical and mechanical interface for PCI Express is not compatible with the PCI bus interface. This is a serial bus which uses two low-voltage differential LVDS pairs, at 2. 5Gb/s in each direction [one transmit, and one receive pair]. A PCI Express link is comprised of these two unidirectional differential pairs each operating at 2. 5Gbps to achieve a basic over all throughput of 5Gbps [before accounting for over-head]. PCI Express uses 8B/10B encoding [each 8 bit byte is translated into a 10 bit character in order to equalize the numbers of 1`s and 0`s sent, and the encoded signal contains an embedded clock]. PCI Express supports 1x [2. 5Gbps], 2x, 4x, 8x, 12x, 16x, and 32x bus widths [transmit / receive pairs]; 2. 5Gigabits/second per Lane per Direction. The 8B/10B changes the data transfer numbers to 250MBps per lane, raw data [B= Bytes, b=Bits]. The reduction in throughput is accounted for under the protocol section. Revision 3. 0 (Gen 3) due out in 2010 increases the speed to 8GT/s and changes the encoding to 128b/130b to reduce the over head. The new bandwidth will increase from 4Gb/s (Gen 2) to 7. 99Gb/s both from over head reduction and bit time reductions. Note; Giga-Transfers per Second (GT/s) The basic LVDS interface is a single differential link in either one or...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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