Bsi bs en 61606 1 2009

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Terms and definitions

For the purposes of this document, the following terms and definitions apply

3.1.1 aliasing components output frequency components below the folding frequency made from the input signal above the folding frequency

3.1.2 analogue full-scale amplitude nominal signal level at the analogue input of an EUT corresponding to the digital full-scale level

The coding format refers to a series of data bit streams that include control information, adhering to the standards for which the Equipment Under Test (EUT) is designed, such as IEC 60958, IEC 61883-6, or various AV interfaces.

NOTE A coding word is arranged as a 2’s complimentary binary form in this standard

Licensed Copy: athen reading, Reading University Library, 23/01/2010 05:08, Uncontrolled Copy, (c) BSI

3.1.4 digital audio signal series of digital signals expressed by sampled data

NOTE This data is constructed with LPCM (Linear Pulse Code Modulation) data

3.1.5 digital interface for measurement type of input or output digital interface which is used for measurement, such as IEC 60958, IEC 61883-6 or some kind of AV interface

NOTE Details are defined in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use)

3.1.6 digital signal generator all types of digital generators, which including digital sine signal generators or package media or RF signal generators

3.1.7 digital zero signal that has a value consisting of all zeroes for all samples

EUT equipment to be measured using the methods described in this standard

3.1.9 folding frequency one half the sampling frequency of the digital system

NOTE Signals applied to the input with frequency components higher than this frequency are subject to aliasing

FS signal level of a sine wave whose positive peak value reaches the positive digital full scale, leaving the negative maximum code unused

EXAMPLE The largest positive value is 7FFFH and the largest negative value is 8001H in 16 bit data

3.1.11 in-band frequency range frequency range from 4 Hz to upper band-edge frequency (see 3.1.19)

3.1.12 jitter deviation of the timing of the transitions of a clock signal from their ideal or nominal times

3.1.13 normal load impedance impedance which is connected to output terminals of EUT

NOTE The concrete value is defined in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use) or IEC 61606-4 (PC use)

3.1.14 normal measuring level signal level equal to –20 dB FS

3.1.15 normal source impedance impedance which is connected to input terminals of EUT

NOTE The concrete value is defined in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use) IEC 61606-4 (PC use)

3.1.16 out-of-band frequencies frequency range from folding frequency to 500 kHz

NOTE Signals applied to the input in this frequency range are subject to aliasing

3.1.17 sampling frequency f s number of samples of a signal taken per unit time

The signal level in dB FS is calculated using the formula: signal level (dB FS) = 20 log₁₀(A/B), where A represents the root mean square (r.m.s.) value of the signal being measured, and B denotes the r.m.s value of a sine wave that corresponds to the full-scale level in digital data or the analogue full-scale level in analogue signals.

3.1.19 upper band-edge frequency frequency calculated by the equation: f s × 0,46

If the sampling frequency (\$f_s\$) exceeds 44.1 kHz, the manufacturer can specify the upper band-edge frequency within the range of 20 kHz to \$f_s \times 0.46\$ This upper band-edge frequency must be clearly indicated in the system description provided by the manufacturer.

3.1.20 word length number of bits of a data element

NOTE The least significant bit of the data element should not be ignored.

Explanation of term “jitter”

Jitter on synchronization or digital audio inputs can significantly impact the performance of conversion processes For instance, if the sampling clock for the analogue-to-digital converter in the Equipment Under Test (EUT) is linked to these inputs, any jitter present can lead to a decrease in conversion accuracy.

Different types of jitter susceptibility include analogue-to-digital jitter susceptibility, digital-to-analogue jitter susceptibility, and digital-to-digital jitter susceptibility For a comprehensive discussion on this topic, refer to AES17.

Rated values

For a full explanation of these terms, see IEC 60268-2 The following are rated conditions for digital audio equipment and should be specified by the manufacturer:

• rated pre-emphasis and de-emphasis characteristics;

• rated digital input word length;

Environmental conditions

Power supply

Supply voltage

The rated power supply voltage must adhere to the specifications outlined in IEC 60038, with a tolerance of ±1% or less In certain cases, a tolerance of up to ±10% may be permissible, provided that the measurement results remain largely unaffected.

Frequency(ies)

The power supply frequency(ies) specified by the manufacturer shall be used The tolerance of the frequency should be ±2 % or less A d.c power supply may be used if specified.

High-frequency and harmonic components (or ripples) in the power

High-frequency components in the power supply output should be less than the level which affects the result of measurement.

Test signal frequencies

The test signal frequency should be chosen from the actual values listed in Table 1 In catalogs and documents where precision is not essential, the standard figures from Table 1 may be used Unless specified otherwise, the reference frequency for measurements is 997 Hz, which can be approximated as 1 kHz in non-critical contexts.

Table 1 – Actual frequencies used in the measurement

If a sweep signal is used in the measurement, the sweep frequency range is from 16 Hz to

Standard setting

Standard input conditions for the EUT

Connect the EUT with the source equipment which has normal source impedance

Connect the EUT to the digital interface, for which the EUT is designed

See IEC 60107-5, IEC 61079-4 and IEC 61079-5.

Standard output conditions for the EUT

Analogue output terminals which are connected to subsequent equipment shall be terminated with the normal load impedance

Digital audio output terminals shall be terminated in a manner appropriate to the output interface format.

Standard setting of controls

The following settings apply a) Each channel of the EUT is set to the standard input and output conditions b) Setting of level controls

For analogue-in/digital-out devices:

When a sinusoidal input signal of 997 Hz is applied to the input terminals of the Equipment Under Test (EUT), adjust the level control to achieve the normal measurement level at the digital output If the EUT lacks a digital output terminal and only records data onto media, ensure the level control is adjusted to record the normal measurement level onto the recording media.

For digital-in/analogue-out devices:

When a 997 Hz sinusoidal signal is applied to the digital input terminal of the Equipment Under Test (EUT), adjust the level control to achieve an analog output signal at the normal measurement level across the analog output terminals, ensuring a normal load impedance is maintained.

To ensure accurate measurements, the level control should be adjusted to its maximum position if the output level fails to reach the normal measurement level Additionally, if the Equipment Under Test (EUT) features a balance control, it must be positioned at the center Furthermore, proper settings for pre-emphasis and de-emphasis are essential for optimal performance.

If pre-emphasis and/or de-emphasis are optional then they shall be turned off, if possible

For measurements requiring pre-emphasis or de-emphasis, the results must be reported separately, along with the specific emphasis characteristics utilized Additionally, the configuration of other controls should be clearly defined.

To ensure a flat frequency response of the Equipment Under Test (EUT), all tone controls, inter-channel balance controls, and other specified settings must be adjusted according to the manufacturer's guidelines It is recommended to turn off the loudness control and filters; if this is not feasible, this limitation should be noted in the results Additionally, the status of any other controls that may influence the audio signal must be documented alongside the results.

Preconditioning

The equipment must be connected under normal operating conditions for the manufacturer's specified preconditioning period to ensure stabilization before measurements are taken If the manufacturer does not specify a preconditioning period, a one-hour duration will be assumed In cases where operational requirements prevent preconditioning, the manufacturer must indicate this.

Should power to the equipment be interrupted during the measurement, sufficient time shall be allowed for restabilization to be realized

Measuring instruments

General

Analogue measuring instruments are effective for systems up to 20 bits, as the quantization noise in a 24-bit system falls below the thermal noise generated by the input impedance of these instruments.

Definitions given in this standard are elementary functions of measuring instruments

Then these definitions can be applied not only to a discrete measuring instrument but also to a combined measuring instrument

Instruments that are ready for use may require a register to be connected across their input terminals if their input impedance does not meet the specified definition in this clause, ensuring the correct value is achieved.

Signal generator

Output impedance: normal source impedance

Output signal level: up to 3 dB over the analogue full-scale amplitude

Distortion: distortion of the signal generator shall be less than a level which does not affect the performance of EUT

The digital signal generator shall be able to supply coding format of digital audio signal A signal is calculated from ideal sine wave form

Output interface format: digital interface for measurement

Frequency error: error is less than 1/f s

Output signal level: from zero level to full-scale level

Error accuracy: better than 1/2 LSB

4.6.2.2 Signal generator for inter-modulation measurement

A generator for inter-modulation measurement shall generate the two-tone signal, composed of 60 Hz (or 70 Hz) and 7 kHz mixed at a ratio of 4:1

In the case of digital signal generator, the peak level of the signal is the same as the peak level of full-scale level

In the case of analogue signal generator, the peak level of the signal is the same as analogue full scale amplitude

It is desirable that the test signal for CCIF inter-modulation test (11 kHz + 12 kHz) is also available from the generator

4.6.2.3 Signal generator for group delay measurement

The analogue signal generator for group delay measurement shall generate a test signal with the waveform of Figure 1

Figure 1 – Analogue test signal waveform

The standard repetition rate of the signal is 4 Hz However, if the input signal level is insufficient for accurate operation of an analogue group delay meter, alternative repetition rates, as specified in Table 2, may be utilized.

The digital signal generator for group delay measurement for digital interface, packaged media and digital broadcast, shall generate a test signal with the waveform of Figure 2

Figure 2 – Digital test signal waveform

The standard repetition rate of the signal is 4 Hz However, if the input signal level is insufficient for accurate operation of a digital group delay meter, an alternative repetition rate, as specified in Table 2, may be utilized.

This digital group delay meter should synchronously have analogue output, having the same waveform as the digital data waveform

A digital packaged medium can be utilized when it produces signals that align with the digital sine signal generator, as well as the signal generators used for inter-modulation and group delay measurements.

An RF signal generator is essential for applications where a modulated output aligns with a digital sine signal generator, particularly in inter-modulation and group delay measurements.

Filter

Input impedance: normal load impedance

Transmission distortion: no effect shall be observed to the measured values

Pass band 4 Hz to upper band-edge frequency

Ripple: less than ±0,3 dB Stop band 0,55 f s and above

If upper band-edge frequency is not 0,46 f s, then the stop band is upper band- edge frequency + f s × 1/10 and above

4.6.3.3 Out-of-band filter (analogue)

Transmission distortion: no effect shall be observed to the measured value

Frequency range: Upper band-edge frequency + (1/10 × f s) to 500 kHz Ripple: less than ± 0,3 dB

Lower stop frequency Frequency range: below the upper band-edge frequency Attenuation: more than 60 dB

Upper stop frequency Frequency range: above 500 kHz Attenuation: more than 18 dB/octave

4.6.3.4 Narrow band-pass filter (analogue and digital)

For analogue signal a) Input impedance: normal load impedance b) Output impedance: normal source impedance

Applicable to digital interface for measurement

No effect shall be observed to the measured values

Pass band: ripple: less than ±0,3 dB at measuring frequency

Stop band: attenuation: more than −60 dB at half and twice the measuring frequencies

4.6.3.4.4 Centre frequency of the filter

The centre frequencies of the narrow band pass filter shall comply with Table 1

Two types of weighting filter may be used

One is the weighting filter which shall comply with ITU-R BS 468-4

Another weighing filter used shall have A-weighing characteristics with tolerances less than

1 dB as specified for sound level measurements in IEC 61672-1

The selection of the filter shall be defined in the corresponding methods.

Level meter

A digital level meter shows the r.m.s level as dB FS

Frequency range: in-band frequency range

NOTE All of the frequency range may be used if the calculation data is not affected

Measuring range: FS to 1 LSB

Error: less than 1 % of reading or 1/2 LSB The larger value is applied

Input interface format: Applicable to digital interface for measurement

Details: The details are defined in IEC 61606-2 (consumer use) or

IEC 61606-3 (professional use) or IEC 61606-4 (PC use), as appropriate

4.6.4.2 Analogue in-band level meter

The analogue in-band level meter indicates the r.m.s value of a sinusoidal signal

Frequency range: from 4 Hz to upper band-edge frequency

Input impedance: in the case of measuring EUT output directly: Normal load impedance, other cases: 100 kΩ or more Measuring range: +30 dB to –115 dB (0 dB = 1 V r.m.s.)

Error: less than 2 % of a full-scale value in the frequency range

NOTE If the analogue in-band level meter has not sufficient sensitivity, a voltage amplifier may be added before the analogue in-band level meter

4.6.4.3 Analogue out-of-band level meter

The analogue out-of-band level meter indicates the r.m.s value of a sinusoidal signal

Frequency range: from upper band-edge frequency to 500 kHz

Error: error is less than 2 % of a full-scale value in the frequency range

Measuring range: 0 dB to –100 dB ( 0 dB = 1 V r.m.s.)

Distortion meter

A distortion meter must effectively measure harmonics and noise by eliminating the fundamental frequency component The results should be presented as a percentage, representing the root mean square (r.m.s.) value ratio of harmonics and noise to the total signal.

Error: less than ± 3 % of full scale value of the measuring range

NOTE If the analogue distortion meter has not sufficient sensitivity, a voltage amplifier may be added before the analogue in-band level meter

Calculate a ratio of the total signal output to the noise and distortion component They are calculated as an r.m.s value The result is shown in %

Input interface format: applicable to digital interface for measurement

Frequency range: signal components are calculated from 4 Hz to the upper band- edge frequency

Measuring signal level: 2 bits below FS to 1 LSB

Error: less than 3 % of the reading or 1 LSB The larger value is applied

The details are defined in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use) or IEC 61606-4 (PC use), as appropriate.

Frequency meter

The tolerance of frequency is less than 1 %.

Group delay meter

If input data is an analogue signal, it is converted to digital data whose accuracy should be better than 16 bits

The delay time of 997 Hz is calculated by the phase delay Φ R ° which is calculated at 997 Hz by Fourier transformation This delay time τR is calculated by the following equation τR = (–Φ R °/360) × (1/997)

The measurement frequency's delay time is determined by the phase delay Φ R °, which is obtained through Fourier transformation This delay time, denoted as τC, is calculated using the equation τC = (–Φ C °/360) × (1/f) Additionally, the digital group delay τ is computed with the formula τ = τC – τR.

Input impedance: If the input signal is analogue, the input impedance shall be normal load impedance of the EUT

Input interface format: If the input signal is digital, confirm to the interface format of the

Accuracy: The processing error shall be less than 0,1 μs for a magnitude of the impulse response signal of larger than 1/8 of FS

Typically, the volume of data exceeds the number of frequency samples (f s) However, if the input signal level is insufficient for calculating phase delay, the data presented in Table 2 can be utilized.

Table 2 – Impulse conditions and measuring range

Condition of data Normal case sufficient data Small data case

5,4 Hz to 100 Hz 100 Hz to upper band-edge frequency 44,1 kHz

Impulse repetition rate 4 Hz 40 Hz

11 Hz to 200 Hz 200 Hz to upper band-edge frequency 88,2 kHz

21 Hz to 400 Hz 400 Hz to upper band-edge frequency

Analogue spectrum analyzer

The spectrum analyzer must analyze frequency spectra of an analog signal up to at least 50 kHz, ensuring adequate frequency accuracy and dynamic range Additionally, it should measure the group delay of the output signal from the Equipment Under Test (EUT) by assessing the response waveform of the group delay measurement signal.

Input impedance: higher than 10 times the normal load impedance.

Digital waveform monitor

The digital waveform monitor shall display the actual transmitting digital audio data The display may be either in real time or display of stored data in memory

The X-axis represents time, while the Y-axis displays the amplitude of audio data The minimum time regulation is determined by \$1/f_s\$, and the maximum full-scale signal level corresponds to the full-scale level Additionally, this digital waveform monitor must be capable of displaying analog signals as well.

Input interface format: confirm to the interface format of the EUT.

Voltage amplifier

Frequency response: from 4 Hz to the upper band-edge frequency

Maximum output level: more than 2 V r.m.s

Distortion and noise: sufficiently smaller than the EUT

A voltage amplifier is essential when the distortion meter lacks the necessary dynamic range for accurate measurements Additionally, if the analogue in-band level meter is unable to measure within an adequate range, utilizing a voltage amplifier can enhance its performance.

Standard digital player

The digital media player must accurately reproduce a stored digital audio signal from the packaged media and transfer it to the digital interface without altering the signal Input data involves measuring the signal recorded on the recording medium by the Equipment Under Test (EUT) The output signal is the reproduced recording, which is transferred to other equipment via the digital interface for measurement It is essential that the output digital data is free from any errors originating from the recording medium.

5 Methods of measurement (digital-in/analogue-out)

General

This clause describes the concept of measurement Concrete procedures are described in IEC 61606-2 for consumer use or IEC 61606-3 for professional use or IEC 61606-4 for PC use

The measurement methods outlined in the subsequent sections pertain to equipment that receives a digital audio signal as input and produces an analogue signal as output When the equipment under test (EUT) features multiple channels, it is essential to measure all channels using the same methodology.

Input/output characteristics

Maximum output amplitude

This test evaluates the maximum output amplitude across the load while ensuring that the output active devices do not saturate The input signal used is a full-scale 997 Hz signal If the Equipment Under Test (EUT) features a level control, the maximum output level may exhibit up to 1% distortion.

If the EUT has no level control, maximum output amplitude is a level when a full-scale level signal is applied

The details are defined in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use) or IEC 61606-4 (PC use) as appropriate.

Gain difference between channels and tracking error

For 2-channel equipment, the test evaluates the gain difference between the left (L) and right (R) channels In the case of multi-channel equipment, the test assesses the gain difference between the channel with the maximum gain and the channel with the minimum gain.

The input signal is normal measuring level and 997 Hz

The gain difference is the value which is measured at the maximum position of the gain control

The tracking error is the gain difference between channels when a level control is adjusted from the maximum level to the rated level

Frequency characteristics

Frequency response

This test evaluates the frequency response of an audio channel in the Equipment Under Test (EUT) using a standard input signal level of -20 dB FS The reference frequency for this measurement is set at 997 Hz, and the frequency response at the testing frequency is determined by the gain difference between the reference frequency and the testing frequency.

Group delay (phase linearity)

This test measures the delay time difference between the component of 997 Hz signal and the measuring frequency signal

The group delay measurement utilizes a digital impulse signal generated by the signal generator The analogue output signal from the Equipment Under Test (EUT) is then converted into a digital signal by the group delay meter.

First, calculate the phase delay value at 997 Hz data and the measuring frequency by the group delay meter

Second, each delay time is calculated from these phase delay values

Finally, the group delay of the measuring frequency is calculated by the difference of these two delay times

If phase linearity at the measured frequency is needed, calculate the phase from the group delay time at the measured frequency

The details are defined in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use) as appropriate.

Noise characteristics

Signal-to-noise ratio (idle channel noise)

This test evaluates the ratio of the root mean square (r.m.s.) value of the full-scale level output at 997 Hz to the noise output with a digital zero input It specifically focuses on the analogue signal processing circuit involved in this measurement.

The D/A converter in BSI equipment remains inactive due to a digital zero input signal, as outlined in section 3.1.7 This results in a distinct signal-to-noise ratio compared to conventional analogue equipment, which continues to operate even in the absence of an input signal.

Dynamic range

This test evaluates the noise level while the signal processing circuitry of the Equipment Under Test (EUT) is operational To prevent non-linear distortion, the input signal is set at –60 dB FS Distortion and noise are quantified using a distortion meter, with results expressed in A dB A weighting filter is applied prior to measurement, focusing primarily on noise signals The dynamic range is determined by the formula (A + 60) dB.

Out-of-band noise ratio

This test measures a noise ratio, which is calculated between the full-scale level signal of

997 Hz and the noise level in the out of band frequency range

Channel separation

This test measures the output level of interference signals which are caused from another channel signal

For multi-channel equipment under test (EUT), it is essential to conduct tests on all inputs, with the worst value determined as the channel separation In this scenario, the interference signal is processed through a D/A converter, revealing any leakage of the interference signal The signals measured represent the fundamental component of the interference signal, excluding harmonics.

The details are defined in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use) or IEC 61606-4 (PC use) as appropriate

Distortion characteristics

Level non-linearity

This test measures the deviation from the linearly proportion between the output signal and the input signal The frequency of test signal is 997 Hz

The measured signal shall be the fundamental component and it does not include noise or distortion

Distortion and noise

This test evaluates the distortion and noise levels as a percentage, calculated by the ratio of the root mean square (r.m.s.) voltage of noise and distortion to the total output r.m.s voltage at a specified frequency The noise and distortion are measured within the in-band frequency range.

Intermodulation

This test measures intermodulation arising from large signal non-linearity effects as described in IEC 60268-3

The details are defined in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use) as appropriate

6 Methods of measurement (analogue-in/digital-out)

General

This clause describes the concept of measurement Specific procedures are described in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use) or IEC 61606-4 (PC use).

Input/output characteristics

Analogue to digital level calibration

This test measures the correlation between the analogue input signal level and digital output signal level

The analogue full-scale amplitude is calculated by this clause The logical analogue input level corresponding to the digital full-scale output level is the analogue full-scale amplitude

This level is estimated by a digital output signal of –20 dB FS

Maximum allowable input amplitude

This test evaluates the permissible amplitude of the input analog signal to the Equipment Under Test (EUT), with the EUT's level control adjustable to any position The saturation level of the input device is indicated, which refers to the point at which distortion reaches 1%.

Gain difference between channel and tracking error

For 2-channel equipment under test (EUT), the test evaluates the gain difference between the left (L) and right (R) channels In the case of multi-channel EUT, it assesses the gain difference between the channel with the maximum gain and the one with the minimum gain The procedure involves setting the input signal to a normal measuring level; if the output signal is clipped, the input signal level is reduced, and if the output signal is too low for accurate measurement, the input signal level is increased.

The gain difference is the value which is measured at the maximum position of the gain control

The tracking error is the gain difference between channels when a level control is adjusted from the maximum level to the rated level

Frequency characteristics

Frequency response

This test evaluates the frequency response of an audio channel in the Equipment Under Test (EUT) using a standard input signal level of -20 dBFS The reference frequency for this measurement is set at 997 Hz, and the frequency response at any testing frequency is determined by the gain difference between the reference frequency and the testing frequency.

The details are defined in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use) or IEC 61606-4 (PC use) as appropriate

Group delay

This test measures the delay time deference between the component of 997 Hz signal and the measuring frequency signal

The analogue impulse signal is applied from the signal generator for group delay measurement

The first, calculate the phase delay value at 997 Hz data and the measuring frequency by the group delay meter

Second, both of these phase delay data are calculated to the delay time

Finally, the group delay of the measuring frequency is calculated by the difference of these two delay times

If phase linearity at the measured frequency is needed, calculate the phase from the group delay time at the measured frequency

Noise characteristics

Signal-to-noise ratio (idle channel noise)

This test evaluates the unwanted output noise components at the output terminals when an analogue input signal is connected to normal source impedance, with the ratio referenced to the full-scale output level A weighting filter is employed to measure the noise component, aligning it with human listening sensitivity This approach differs from that used in digital-to-analogue systems, as in analogue-to-digital systems, noise signals are typically produced by the A/D converter, and the active audio signal processing circuit contributes to the noise at the output terminal Consequently, measuring the signal-to-noise ratio in this context closely resembles the measurement techniques used for analogue equipment.

The details are defined in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use) or IEC 61606-4 (PV use) as appropriate.

Dynamic range

This test evaluates the noise level while the signal processing circuitry of the Equipment Under Test (EUT) is operational To prevent non-linear distortion, the input signal is set at –60 dB FS Distortion and noise are quantified using a distortion meter, expressed in A dB A weighting filter is applied prior to measurement, as the focus of this test is primarily on noise signals The dynamic range is determined by the formula (A + 60) dB.

Folded noise

This test evaluates the presence of unwanted noise signals within the in-band frequency when an input signal exceeding \$f_s/2\$ is applied to the analogue input of the Equipment Under Test (EUT) The input signal is set to the analogue full-scale amplitude.

Cross-talk

This test evaluates the level of unwanted signals leaking from unrelated channels, focusing on the fundamental component of the interference signal at the selected output terminal when a full-scale interference signal is introduced to an unselected input terminal Unlike digital to analog equipment, which experiences leakage from unselected input terminals to the A/D converter, this test specifically assesses the performance of analogue circuitry.

Channel separation

This test evaluates the output level of interference signals associated with another channel signal For multi-channel equipment, tests are conducted on all inputs, with channel separation defined by the worst value observed This measurement reflects the leakage of the interference signal, focusing solely on the fundamental component and excluding harmonics.

Distortion characteristics

Level non-linearity

This test measures the deviation from the linearly proportion between the output signal and input signal The measured signal is the fundamental component

It does not include noise or distortion The frequency of input signal is 997 Hz

Distortion and noise

This test evaluates the distortion and noise levels as a percentage, calculated by the ratio of the root mean square (r.m.s.) voltage of noise and distortion to the total output r.m.s voltage at a designated frequency The measurement focuses on the in-band frequency range for both noise and distortion.

Intermodulation

This test measures intermodulation arising from large signal non-linearity effects as described in IEC 60268-3

The details are defined in IEC 61606-2 (consumer use) or IEC 61606-3 (professional use) as appropriate

IEC 61938, Audio, video and audiovisual systems – Interconnections and matching values – Preferred matching values of analogue signals

EIAJ CP-2150, Methods for measurement for digital audio equipment

Tiêu đề	Audio And Audiovisual Equipment — Digital Audio Parts — Basic Measurement Methods Of Audio Characteristics — Part 1: General
Trường học	Reading University
Chuyên ngành	Audio and Audiovisual Equipment
Thể loại	British Standard
Năm xuất bản	2009
Thành phố	Brussels

Định dạng
Số trang	34
Dung lượng	1,19 MB