Tim,
My understanding is that GMSK is just Frequency Shift Keying. The acronym stands for Gaussian Minimum Shift Keying. The minimum shift part means that the data and carrier are synchronized so that the data changes happen when the carrier is zero. This removes phase discontinuities. The data is run through a Gaussian filter before it is transmitted. The main objective is to reduce the sideband power. This makes it a very power efficient mode and it is part of the GSM Mobile Phone standard. It is a good choice for something battery powered, like a phone or a small spacecraft. With that said it is harder to decode than straight FSK with a Root Raised Cosine Filter. So it might be better with strong signals than weak ones. That is just my conjecture. I'm sure there is bit error data somewhere that can answer that question.
73
Chris
G0KLA / AC2CZ
On Sat, Mar 20, 2021, 18:14 Timothy Tapio timothytapio1@gmail.com wrote:
I know nothing about GMSK but am interested in learning how to decode it...can someone point me to a good URL for information? I did a search on duckduckgo but wasn't finding anything that was a simple enough explanation for me to understand....
73 de Tim K4SHF
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