ITU-T REC. J.21 – PERFORMANCE CHARACTERISTICS OF 15 kHz TYPE SOUND-PROGRAMME CIRCUITS
1 Application
2 Interface characteristics
    2.1 Test conditions
    2.2 Impedance
    2.3 Levels
3 Overall performance
    3.1 Common parameters
    3.2 Additional parameters for stereophonic programme transmission
    3.3 Additional requirements for digital systems
Bibliography