ITU-R BT 1439-1-2006 Measurement methods applicable in the analogue television studio and the overall analogue television system《应用于模拟电视演播室和整个模拟电视系统的测量方法》.pdf
《ITU-R BT 1439-1-2006 Measurement methods applicable in the analogue television studio and the overall analogue television system《应用于模拟电视演播室和整个模拟电视系统的测量方法》.pdf》由会员分享,可在线阅读,更多相关《ITU-R BT 1439-1-2006 Measurement methods applicable in the analogue television studio and the overall analogue television system《应用于模拟电视演播室和整个模拟电视系统的测量方法》.pdf(37页珍藏版)》请在麦多课文档分享上搜索。
1、 Rec. ITU-R BT.1439-1 1 RECOMMENDATION ITU-R BT.1439-1 Measurement methods applicable in the analogue television studio and the overall analogue television system (Question ITU-R 86/6) (2000-2006) Scope This Recommendation defines measurement methods and test signals used in analogue television syst
2、ems programme verification. The ITU Radiocommunication Assembly, considering a) that proper operation of analogue television studios and of other analogue parts of the television chain requires accurate monitoring of the correct performance of individual sections of the overall system; b) that such
3、monitoring is best performed on analogue video equipment using appropriate analogue video test signals; c) that the methods to measure the correct performance of sections of the analogue television chain, based on the use of analogue video test signals, should desirably be standardized; d) that ITU-
4、T Recommendation J.61 recommends nomenclature and measuring methods for analogue video test signals at baseband, for use on analogue video transmission links; e) that most of the test signals and measuring methods recommended in ITU-T Recommendation J.61 are also applicable and are indeed already wi
5、dely applied to the measurement of the performance of analogue video production chains; f) that, whenever possible, the same measurement signals and measurement methods should desirably be applied throughout the analogue television chain, including both the production sections and the transmission s
6、ections, recommends 1 that the definitions of video parameters at baseband, as given in Part 1 of this Recommendation, should be applied where appropriate to measurement of video baseband parameters in analogue television studios and the overall analogue television system; 2 that the measuring metho
7、ds and test signals, as given in Part 2 and Annex 1 to this Recommendation, should be used where appropriate to perform measurements at video baseband in analogue television studios and the overall analogue television system; 3 that the design for filters, as given in Annex 2 to this Recommendation,
8、 for application to specific measuring methods should be used where appropriate, when performing similar measurements at video baseband in analogue television studios and the overall analogue television system; 2 Rec. ITU-R BT.1439-1 4 that, when it is desired to perform on-line measurements of perf
9、ormance at video baseband in the overall analogue television system in the presence of programme signals, the measurement methods and insertion test signals given in Annex 3 to this Recommendation should be applied where appropriate; 5 that the K-rating methods of assessment given in Annex 4 to this
10、 Recommendation for the measurement of short-term waveform distortion may also usefully be applied to measurements in the analogue television studio and the overall analogue television system, if desired. NOTE 1 Measurement methods for digital television equipment with analogue input and output are
11、defined in Recommendation ITU-R BT.1204. Measuring methods and test signals are the same as in ITU-T Recommendation J.61. PART 1 Definitions of video parameters 1 Waveform terminology The following terms concerning the components and values of a composite colour video signal are illustrated in Fig.
12、1: A : the non-useful d.c. component B : the useful d.c. component, integrated over a complete frame period C : the picture d.c. component, integrated over the active line period, TuD : the instantaneous value of the luminance component E : the instantaneous signal value with respect to the bottom o
13、f the synchronizing pulses F : the peak signal amplitude (positive or negative with respect to blanking level) G : the peak amplitudes of chrominance components H: the peak-to-peak signal amplitude J : the difference between black level and blanking level (set-up) K : the peak-to-peak amplitude of t
14、he colour burst L : the nominal value of the luminance component M : the peak-to-peak amplitude of a monochrome composite video signal (M = L + S) S : the amplitude of the synchronizing pulses Tsy: duration of line synchronizing pulse Tlb: duration of line blanking period Tu: duration of active line
15、 period Tb: duration of breezeway Tfp: duration of front porch Tbp: duration of back porch. The amplitudes L, S and M are used as reference amplitudes for the video signal. The amplitudes defined by B, C, D, E, F, G, H and J above, may be expressed as percentages of the value L. Rec. ITU-R BT.1439-1
16、 3 Average picture level (APL) is the mean value of C over a complete frame period (excluding blanking periods) expressed as a percentage of L. 2 Definitions of signal parameters 2.1 Nominal impedance, Z0The input and output impedance, Z0of each device should be specified, as either unbalanced or ba
17、lanced with respect to earth. 2.2 Return loss The return loss, relative to Z0, of an impedance Z is, in the frequency domain: dB)()(log2000fZZfZZ+In the time domain, it is expressed by the symbolic formula: dBlog2021AA4 Rec. ITU-R BT.1439-1 where A1is the peak-to-peak amplitude of the incident signa
18、l and A2is the peak-to-peak amplitude of the reflected signal. Numerically, the result is the same as that obtained by the frequency domain method if the return loss is independent of frequency. 2.3 Polarity and d.c. component The polarity of the signal should be positive, that is to say, such that
19、black-to-white transitions are positive-going. The useful d.c. component, B in Fig. 1, which is related to the average luminance of the picture, may or may not be contained in the signal and need not be transmitted or delivered at the output. A non-useful d.c. component, A in Fig. 1, may be present
20、in the signal (for example, due to d.c. supplies). Limits for this component need to be specified for the terminated and unterminated conditions. 2.4 Nominal signal amplitude The nominal signal amplitude is the peak-to-peak amplitude of the monochrome video signal that includes the synchronizing sig
21、nal and luminance signal component set to peak-white (M in Fig. 1). 3 Definitions of performance parameters The definitions in 3.2 and the subsequent sub-sections assume that the equipment has nominal insertion gain as defined in 3.1. 3.1 Insertion gain Insertion gain is defined as the ratio, expres
22、sed in decibels, of the peak-to-peak amplitude of a specified test signal at the receiving end to the nominal amplitude of that signal at the sending end, the peak-to-peak amplitude being defined as the difference between the amplitudes measured at defined points of the signal used. 3.2 Noise 3.2.1
23、Continuous random noise The signal-to-noise ratio for continuous random noise is defined as the ratio, expressed in decibels, of the nominal amplitude of the luminance signal, L in Fig. 1, to the r.m.s. amplitude of the noise measured after band limiting. A signal-to-weighted-noise ratio is defined
24、as a ratio, expressed in decibels, of the nominal amplitude of the luminance signal, L in Fig. 1, to the r.m.s. amplitude of the noise measured after band limiting and weighting with a specified network. The measurement should be made with an instrument having, in terms of power, a defined time cons
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