In computing, a computer bus operating with double data rate transfers data on both the rising and falling edges of the clock signal. This is also known as double pumped, dual-pumped, and double transition. RAM (Random Access Memory) Look up computing in Wiktionary, the free dictionary. ... In computer architecture, a bus is a subsystem that transfers data or power between computer components inside a computer or between computers and typically is controlled by device driver software. ... In synchronous digital electronics, such as most computers, a clock signal is a signal used to coordinate the actions of two or more circuits. ...

The simplest way to design a clocked electronic circuit performs one transfer per full cycle (rise and fall) of a clock signal. This, however, requires that the clock signal operate twice as fast as the data signals, which change at most once per transfer. When operating at high speed, signal integrity limitations constrain the clock frequency. By using both edges of the clock, the data signals operate at the same limiting frequency, doubling the data transmission rate. An electronic circuit is an electrical circuit that also contains active electronic devices such as transistors or vacuum tubes. ... In synchronous digital electronics, such as most computers, a clock signal is a signal used to coordinate the actions of two or more circuits. ... Signal Integrity, sometimes known as SI, refers to electronic circuit tools and techniques that ensure electrical signals are of sufficient quality for proper operation. ... FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. ...

This technique has been used for microprocessor front side busses, Ultra-3 SCSI, the AGP bus, DDR SDRAM, and the HyperTransport bus on AMD's Athlon 64 processors. In computers, the front side bus (FSB) or system bus is the physical bi-directional data bus that carries all electronic signal information between the central processing unit (CPU) and the northbridge. ... This article or section does not cite any references or sources. ... This article does not cite any references or sources. ... DDR SDRAM or double-data-rate synchronous dynamic random access memory is a type of memory integrated circuit used in computers. ... HyperTransport logo HyperTransport (HT), formerly known as Lightning Data Transport (LDT), is a bidirectional serial/parallel high-bandwidth, low-latency point to point link that was introduced on April 2, 2001. ... Advanced Micro Devices, Inc. ... The Athlon 64 is an eighth-generation, AMD64 architecture microprocessor produced by AMD, released on September 23, 2003[1]. It is the third processor to bear the name Athlon, and the immediate successor to the Athlon XP[2]. The second processor (after the Opteron) to implement AMD64 architecture and the...

An alternative to double or quad pumping is to make the link self-clocking. This tactic was chosen by InfiniBand and PCI Express. In telecommunications and electronics, a self-clocking signal is one that can be decoded without need for a separate clock signal or other source of synchronization. ... InfiniBand is a switched fabric communications link primarily used in high-performance computing. ... PCI Express (formerly known as 3GIO for 3rd Generation I/O, not to be mistaken with PCI-X) is an implementation of the PCI computer bus that uses existing PCI programming concepts and communications standards, but bases it on a much faster serial communications system. ...

Describing the speed of a double-pumped bus can be confusing. Each clock edge is referred to as a "beat", with two beats (one upbeat and one downbeat) per cycle. Some people talk about the basic clock frequency, while others refer to the number of transfers per second. Careful usage generally talks about "500 MHz, double data rate" or "1000 MT/s", but people will refer casually to a "1000 MHz bus", even though no signal cycles faster than 500 MHz. putang ina. ... Anacrusis in poetry is the lead-in syllables that precede the first full measure, while, similarly, in music, it is the note or notes (even a phrase) which precede the first downbeat in a group. ... Downbeat can have several meanings: // In Music Theory In music performance and music theory, the downbeat is also the first beat of a measure in music. ...

DDR SDRAM popularized the technique of referring to the bus bandwidth in megabytes per second, the product of the transfer rate and the bus width in bytes. DDR SDRAM operating with a 100 MHz clock is called DDR-200 (after its 200 MT/s data transfer rate), and a 64 bit (8 byte) wide DIMM operated at that speed is called PC-1600, after its 1600 MB/s peak (theoretical) bandwidth. A megabit per second (Mbps or Mbit/s) is a unit of data transmission equal to 1,000 kilobits per second or 1,000,000 bits per second. ... Two types of DIMMs: a 168-pin SDRAM module (top) and a 184-pin DDR SDRAM module (bottom). ...

See also

• DDR SDRAM, DDR2 SDRAM, and DDR3 SDRAM which all use DDR signalling
• Quadruple data rate