BS 6840-3:1992

Committees responsible
National foreword
Foreword
1. Scope
2. Object
3. Conditions
3.1 Conditions for specifications and measurements
3.2 Rated conditions and standard test conditions
3.3 Other conditions
4. Classes of operation
Section one. General
5. Rated source impedance
6. Interchangeable parts
7. Automatic controls
8. Special instructions for operation
9. Power supply
10. Position of the volume controls
11. Series of measurements
12. Pre-conditioning for measurements
13. Variable consumption apparatus
14. Marking
15. Operating environment
Section two. Characteristics to be specified and the
relevant measuring methods
16. Power supply
16.1 Basic power supply characteristics
16.2 Tolerance of power supply voltage variations
16.3 Tolerance of power supply frequency variations
16.4 Tolerance of power supply harmonics and ripple
17. Input characteristics
17.1 Rated source impedance
17.2 Input impedance
17.3 Rated source e.m.f.
17.4 Minimum source e.m.f. for rated distortion-limited
      output voltage
18. Output characteristics
18.1 Rated load impedance
18.2 Output source impedance
18.3 Output voltage and power (distortion-limited)
18.4 Regulation
18.5 Overload restoring time
19. Limiting characteristics
19.1 Overload source e.m.f.
19.2 Short-term maximum output voltage and power
19.3 Long-term maximum output voltage and power
19.4 Temperature-limited output power
19.5 Characteristic of protection circuits
20. Gain
20.1 Voltage gain and e.m.f. gain
20.2 Maximum e.m.f. gain
20.3 Attenuation characteristic of the volume control
20.4 Attenuation characteristic of balance controls for
      multi-channel equipment
21. Response
21.1 Gain-frequency response
21.2 Gain-limited effective frequency range
21.3 Distortion-limited effective frequency range
21.3 Phase-frequency response
22. Amplitude non-linearity
22.1 Introduction
22.2 Rated total harmonic distortion
22.3 Total harmonic distortion under standard test
      conditions
22.4 Total harmonic distortion as a function of
      amplitude and frequency
22.5 Harmonic distortion of the nth order under
      standard test conditions
22.6 Harmonic distortion of the nth order as a function
      of amplitude and frequency
22.7 Modulation distortion of the nth order
22.8 Difference frequency distortion of the nth order
22.9 Dynamic intermodulation distortion (DIM)
22.10 Total difference frequency distortion
22.11 Weighted (total) harmonic distortion
23. Noise
23.1 Characteristics to be specified
23.2 Method of measurement
24. Hum
24.1 Introduction
24.2 Characteristics to be specified
24.3 Method of measurement
25. Balance
25.1 Balance of the input
25.2 Balance of the output
26. External influences
26.1 General
26.2 Equivalent source e.m.f. for external magnetic
      fields at low frequencies, including the power
      supply frequency and its harmonics
26.3 Residual equivalent source e.m.f. for external
      magnetic fields at the power supply frequency
      and its harmonics
27. Magnetic stray field
27.1 Interfering stray field generated by the amplifier
28. Cross-talk and separation in multi-channel
    amplifiers
28.1 Characteristics to be specified
28.2 Method of measurement
29. Gain and phase differences between channels in
    multi-channel amplifiers
29.1 Gain difference
29.2 Phase difference
30. Dimensions and weight
30.1 Dimensions
30.2 Weight
31. Classification of the characteristics to be
    specified
31.1 General
31.2 Classification
Annexes
Annex A (informative) Bibliography
Annex ZA (normative) Other international publications
         quoted in this standard with the references
         of the relevant European publications
National annex NA (informative) Cross-references
Table
1. Dynamic intermodulation distortion components
    falling into the audio band
Figures
1. Input impedance - Balanced input, centre tap
    connected to earth
2. Input impedance - Unbalanced input, connected to
    earth
3. Overload restoring time
4. Frequency spectrum of the measurement signal below
    30 kHz, for dynamic intermodulation distortion
5. Configuration of the measuring circuit
6. Output current/output voltage characteristic:
    typical display of results

Gives recommendations relative to the characteristics to be specified and the relevant measuring methods for amplifiers. Applies to amplifiers which form part of a sound system for household and professional applications. Coverage includes: automatic controls, power supply, marking, and operating environment. Includes annexes and diagrams.