Howtosignalprocessing
- What is BT in GMSK?
- What is BT in GFSK?
- What is the value for BT bandwidth-time product for GMSK and GFSK?
- What is GMSK used in GSM?
What is BT in GMSK?
As a very bandwidth-efficient modulation format, Gaussian minimum shift keying (GMSK) with a low bandwidth-time (BT) product value is important for bandwidth-limited satellite communications.
What is BT in GFSK?
GFSK modulation is determined by two parameters: the modulation index (h) and the bandwidth of the Gaussian filter. The Gaussian filter is usually characterized by the bandwidth-time product (BT), which is equal to the 3-db bandwidth of the Gaussian filter (B) times the bit period (T).
What is the value for BT bandwidth-time product for GMSK and GFSK?
In GSM telephony for instance, a BT=0.3 is recommended. In satellite communications with GMSK, for near-earth missions the CCSDS recommends a BT=0.25 whilst for deep-space/interplanetary missions, the use BT=0.5 is recommended. You find more details in this CCSDS report on bandwidth-efficient modulations.
What is GMSK used in GSM?
GMSK – Gaussian minimum shift keying – is the original circuit switched GSM modulation system, allowing the GSM radio channel to be modulated at a data rate of 271kb/s whilst keeping the radio channel within a 200kHz bandwidth. This is the modulation system used for circuit switched and GPRS operations.
