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+# Generating audio signals
+
+In order to generate sound for this project, a few posibilities exist (see chapters below)
+
+## Sound chips
+
+A sound chip is made to use digital, analog or mixed signals and produce a tone or sound based on that. 
+
+
+| Manufacturer       | Chip                                                                                                          | Year | Channels | Stand-alone | Cost/availability |
+| ------------------ | ------------------------------------------------------------------------------------------------------------- | ---- | -------- | ----------- | ----------------- |
+| Atari, Inc.        | [POKEY](https://en.wikipedia.org/wiki/POKEY)                                                                  | 1979 | 4        | Somewhat    | N/A               |
+| General Instrument | [AY-3-8910](https://en.wikipedia.org/wiki/AY-3-8910)                                                          | 1978 | 3        | Yes         | N/A               |
+| General Instrument | [SP0250](https://en.wikipedia.org/wiki/General_Instrument_SP0256)                                             | 1981 | 1        | Yes         | N/A               |
+| Konami             | [VRC6](https://en.wikipedia.org/wiki/VRC6)                                                                    | 1987 | 3        | Yes         | N/A               |
+| Philips            | [Philips SAA1099](https://en.wikipedia.org/wiki/Philips_SAA1099 "Philips SAA1099")                            | 1984 | 6        | Yes         | N/A               |
+| Sunsoft 5B         | [Sunsoft 5B](https://en.wikipedia.org/wiki/Memory_management_controller#FME-7 "Memory management controller") | 1992 | 3        | Yes?        | N/A               |
+| Texas Instruments  | [SN76477](https://en.wikipedia.org/wiki/SN76477)                                                              | 1978 | 1        | Yes         | N/A               |
+| Texas Instruments  | [SN76489](https://en.wikipedia.org/wiki/SN76489 "SN76489")                                                    | 1980 | 4        | Yes         | N/A               |
+| Texas Instruments  | [Sega PSG (SN76496)](https://en.wikipedia.org/wiki/SN76496 "SN76496")                                         | 1982 | 4        | Yes         | N/A               | 
+
+This chart shows different audio chips that might have been used in retro consoles. While all of them aren't easily available anymore it is still interesting to take a close look at how these IC's (Intergrated Ciruit) work. 
+
+Most chips work on one of two pricibles, this being either a "Programmable sound generator" or "Sound Chip"
+
+
+### Programmable sound generator (PSG)
+
+PSG's are a subset of sound chips that generate sound based on a set of pre programmed tones they can generate. For example, this can be done by: modulating a input square wave to a different frequency and or amplitude.
+
+### Pulse-code modulation
+
+Pulse-code modulation uses pre-sampled data to generate sounds. This causes a lot more work for the engineer before gaining a working system. The flip side of that coin is that the Output can be of a better quality (depending on the sampled audio used).
+
+## FPGA Circuit
+