Which ASK-OOK line code has the lowest error rate? - Page 1
Forum section: electronics / rf-microwave

author: Faranight
author_rank: Unknown
timestamp: April 14, 2025, 02:32:53 pm
content: Hey, question about data reception quality. I'm working with amateur stuff here, so think Raspberry Pi. Assume a device with a very simple transmitter on an ISM band - most of these consumer devices use simple means of communication. By switching a transmitter on/off in a predefined manner they encode information into a carrier signal. This is calledamplitude shift keying - on/off keying. Think of it like a Morse code of sorts. The encoding type is usually called aline code, and there are several known.Non-return-to-zerois the simplest one as every bit being transmitted is directly mapped to the transmitter switch. When transmitter is on, we are transmitting a digital one, when it's off we're "transmitting" a digital zero. This line code is not balanced, as it may have a DC component that may affect how receivers perceive the signal. There's also difficulty recovering clock from the signal.Pulse-width modulationwhere the binary data is typically encoded as pulses of different lengths. Usually there are two lengths - the long one representing a digital one and the short one representing a digital zero.Pulse-position modulationis a line code where data is encoded in varying time duration between quick transmitter pulses. This line code has supposedly very low power consumption and is often employed by battery-powered consumer devices.Manchesteris a modulation that has embedded clock transitions in the signal. The signal alternates between clock and signal transitions. Clock transitions are always present while signal transition can be present or absent depending on what bit is being transmitted.Othersthat I haven't listed here. Some of the above may feature inverted types as well as differential types.Now suppose there is a transmitter like this and a receiver some distance apart. Both of them are tuned to the same frequency i.e. 433,92 MHz ISM band and have the same antennas. The transmitter then transmits some binary data of given length multiple times in a row with the same data rate and an equal transmit power. The only difference is that it is transmitting the given data with different line codes. During transmission, both devices are located same distance apart in the same environment with the same noise floor.Question:Which line code has the lowest error rate on the receiver as the distance between the two endpoints is increasing? In other words, what line code should be used to minimize the data error rate over a given distance when other parameters are unchanged. Have there been any experiments on this? Yes, I know I could change the hardware, if I wanted better reception, but this question is about OOK line codes.EDIT: Yes, I know I can also use software bit correction, but this question is still about line codes.

author: Andy Chee
author_rank: Super Contributor
timestamp: April 15, 2025, 02:29:11 am
content: My vote is for delay modulation / MFM / (1,3) RLLhttps://messui.polygonal-moogle.com/comp/RLL_encoding.pdf(yes, the linked papers refer to magnetic data storage, but this code can be used with OOK as well)