Editing Vectrex (section)

==Design and technical specifications==
[[File:Vectrex---Block-Diagram.png|thumb|Block Diagram]]
[[File:Vectrex---Logic-Board-Schematic.png|thumb|Logic Board Schematic]]
The Vectrex's [[Central processing unit|CPU]] is a [[Motorola 6809|Motorola 68A09]] clocked at 1.5&nbsp;[[Hertz|MHz]], with 1&nbsp;[[Kilobyte|KB]] of [[Random-access memory|RAM]] (two 4-bit 2114 chips) and 8&nbsp;KB [[Read-only memory|ROM]] (one 8-bit 2363 chip). It also uses a [[MOS Technology 6522]] [[Peripheral Interface Adapter|versatile interface adapter (VIA)]]. Games are stored on [[ROM cartridge|ROM cartridges]] that are 32&nbsp;KB in size. Controller inputs and audio are provided by a [[General Instrument AY-3-8910|General Instrument AY-3-8912]] [[sound chip]]. <ref>{{cite web | title=Vectrex Service Manual | url=https://wiki.console5.com/tw/images/a/a7/Vectrex-Service_Manual.pdf}}</ref> Sound is played through a 3-inch electrodynamic paper cone speaker.

The computer and vector generator were designed by Gerry Karr. The computer runs the game's computer code, watches the user's inputs, runs the sound generator, and controls the vector generator to make the screen drawings. The vector generator is an all-analog design using two integrators: X and Y. The computer sets the integration rates using a digital-to-analog converter. The computer controls the integration time by momentarily closing electronic analog switches within the operational-amplifier based integrator circuits. Voltage ramps are produced that the monitor uses to steer the [[electron beam]] over the face of the phosphor screen of the cathode-ray tube. Another signal is generated that controls the brightness of the line.

The [[cathode-ray tube]] is a [[Samsung]] model 240RB40 [[monochrome monitor|monochrome]] unit measuring 9 × 11&nbsp;inches, displaying a picture of 240&nbsp;mm diagonal; it is an off-the-shelf picture tube manufactured for small black/white television sets. The brightness of the CRT is controlled using a circular knob on the back of the display. A vector CRT display such as the one in the Vectrex does not require a special tube, and differs from standard raster-based television sets only in the control circuits. Rather than use [[sawtooth wave]]s to direct the internal electron beam in a [[raster scan|raster]] pattern, computer-controlled [[integrator]]s feed linear amplifiers to drive the deflection yoke. This yoke has similar, if not identical inductances, unlike a TV deflection yoke. The yoke uses a standard TV core. The high-voltage [[flyback transformer|transformer]] also uses a standard core and bobbin. There is special circuitry to turn off the electron beam if the vector generator stops or fails. This prevents burning of the screen's [[phosphors]]. This design is a great deal smaller than the electronics found in the free-standing, full-sized ''[[Asteroids (arcade game)|Asteroids]]'' arcade machine.

During development, the possibility of using the [[MOS Technology 6502]] processor was considered, but later its performance was considered insufficient.<ref>{{cite web | title=Vectrex Programmers Guide – Project Breaker and the 6502 Vectrex | url=https://roadsidethoughts.com/vectrex/breaker-and-the-6502.htm}}</ref>

Early units have a very audible "buzzing" from the built-in speaker that reacts to the graphics generated on screen. This is due to improper production grounding of signal lines of the low-level audio circuitry, and was eventually resolved in later production models. A "[[ground loop (electricity)|ground loop]]" had been created by a grounding strap added in production to meet U.S. [[Federal Communications Commission]] signal radiation requirements.{{Citation needed|date=March 2008}} This idiosyncrasy has become a familiar characteristic of the machine.