FIELD: electronic engineering. SUBSTANCE: device functions to decode coherent signal modulated by multilevel phase keying with differential coding of characters. Coherent signal modulated by phase keying with differential coding of characters goes to coherent receiver which passes it to metric calculator. The latter generates soft solution metric 
corresponding to coherent signal modulated by mentioned method which is passed to direct error correction decoder. The latter decodes mentioned coherent signal in compliance with soft solution metric 
corresponding to mentioned coherent signal. EFFECT: facilitated decoding of coherent signal modulated by multilevel phase keying with differential coding of characters. 10 cl, 3 dwg
