ANSI SMPTE ST 11-1995 Video Recording - Quadruplex Recorders Operating at 7.5 in s - Audio Level and Multifrequency Test Tape.pdf

1、SUPTE LL 95 835VOL OOOLB V95 SMPTE STANDARD ANSI/SMPTE 11-1995 Revision of ANSVSMPTE 11-1989 for Video Recording - Quadruplex Recorders Operating at 7.5 in/s - Audio Level and MuKiequency Test Tape 1 Scope This standard specifies an audio frequency test tape to be used for adjusting the sensitivity

2、and frequency response of audio 1 record (program audio track) and audio 2 record (cue track) of quadruplex video magnetic tape recorders operating at a tape speed of 7.5 inls (190.5 mmls). The tape shall be used on recorders, operating in accordance with ANSIlSMPTE 3. The operating level and freque

3、ncy response for audio 2 record are specified in SMPTE RP 102. 2 Normative references The following standards contains provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to

4、 revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. ANSI 54.3-1 982 (R1992), Method for Measurement of Weighted Peak Flutter of Sound Recording and Reproducing Equipment ANSI S

5、4.6-1982 (R1992), Method of Measuring Recorded Flux of Magnetic Sound Records at Medium Wavelengths Page 1 of 6 pages ANSVSMPTE 4-1 995, Television Analog Recording - 2-in Magnetic Tape for Quadruplex Recording -Speed ANSI/SMPTE 6-1 993, Video Recording - 2-in Quad- ruplex Tape - Video, Audio and Tr

6、acking-Control Records ANSI/IEEE 152-1 992, Audio Program Level Measure- ment SMPTE RP 16-1 993, Specifications of Tracking- Control Record for 2-in Cluadruplex Video Magnetic Tape Recordings SMPTE RP 102-1 991, Frequency Response and Operating Level of Recorders and Reproducers for Audio 2 Record f

7、or 2-in Quadruplex Video Magnetic Tape Operating at 15 and 7.5 inls 3 General Specifications 3.1 Dimensions of records The dimensions of pertinent records constituting this test tape shall conform to ANSIlSMPTE 6. 3.2 Tape speed The nominal linear speed of this test tape shall be 7.5 in/s (1 90.5 mm

8、/s) in accoi,dance with ANSI/SMPTE 4. 3.3 Stock ANSIlSMPTE 1-1 990, Video Recording - 2-in Magnetic Recording Tape ANSIlSMPTE 3-1 992, Television Analog Recording - Frequency Response and Operating Level of Recorders and Reproducers - Audio 1 Record on 2-in Tape Operating at 15 and 7.5 inls The test

9、 sections shall be recorded on transversely oriented television magnetic recording tape, the di- mensions of which are specified in ANSI/SMPTE 1. 3.4 Video signal A color black video signal may be recorded. CAUTION NOTICE This Standard may be revised or withdrawn at any time The procedures of the St

10、andard Developer requiie that action be taken to reaffirm, revise. or withdraw this standard no later than five years from the date of publication Purchasers of standards may receive current information on all standards by calling or writina the Standard Develooer Printed in USA. Copyright O 1995 by

11、 THE SOCIETY OF - American National Standard MOTION PICTURE AND TELEVISION ENGINEERS 595 W Hartsdale Ave, White Pians. NY 10607 (914) 761-1100 Approved February 13,1995 SMPTE 11 75 83574011 00011878 321 ANSI/SMPTE 11-1995 3.5 Tracking-control signal A tracking control signal, conforming to that spec

12、ified in SMPTE RP 16, as applicable, shall be recorded throughout the tape. 3.6 Identification Voice announcement at the beginning of this tape shall provide identification as to the applicable American National Standard, the test tape manufac- turer, and the flux (in nanowebers per meter) of the op

13、erating level test tones defined in 4.1 recorded on audio 1 record and audio 2 record. Each test section and segment shall be preceded by voice an- nouncements at a level approximately 5 dB below operating level identifying the content of that particular recorded segment. 3.7 Flutter The weighted pe

14、ak flutter of this test tape shall not exceed 0.2%. 3.8 Azimuth The azimuth of the signal recorded on the tape shall be 90“ f 3 to the reference edge of the tape. 4 Audio 1 record test sections 4.1 Audio operating level section This section is used to calibrate the sensitivity of the audio reproduci

15、ng system. 4.1.1 Frequency The frequency of the recording shall be 1 O00 Hz f 2% when the tape is reproduced at exactly 7.5 inls (190.5 rn mls) . 4.1.2 Tape flux per unit track width The audio operating level test recording has an rms short circuit tape flux per unit track width of 11 O nWb/m f 3 nW

16、b/m. 4.1.3 Flux level variation The flux level variation during the length of the tone shall fall within an envelope whose total width is 0.5 dB. 4.1.4 Distortion The total harmonic distortion of this section when reproduced shall not exceed 2%. 4.1.5 Duration The minimum duration of this section sh

17、all be one minute. 4.2 Frequency response section Recorded on audio 1 record, this section is to be used to calibrate the frequency response of the audio reproducing system of a quadruplex video magnetic tape recorder. 4.2.1 Frequencies The following test segment frequencies (in hertz) shall be reco

18、rded in the order given: 1 O00 (reference) 4000 63 8000 125 10 O00 250 12 500 500 16 O00 1 O00 1 O00 (reference) 2000 The frequency of each recording shall be within f 2% of its specified value when the tape is reproduced at exactly 7.5 in/s (1 90.5 mm/s). 4.2.2 Tape flux level vs frequency The rela

19、tive short circuit tape flux level versus frequency expressed in decibels shall be as given by the following equation: b (f) re 110 nWb/m = -9.8 t 10 logio l + (Fim2 / l + (f/Fh)* 1 dBl where Ls, is the relative tape flux level; f is the frequency at which the response is being computed; FI is the l

20、ow-frequency transition frequency, 80 Hz; and Fh is the high-frequency transition frequency, 4500 Hz. A graph of this equation is shown in figure 1. The values of the tape flux and relative flux level are given in table 1. Page 2 of 6 pages SMPTE IJL 95 8357403 O003879 268 ANSI/SMPTE 11-1995 RELATIV

21、E LEVEL OF SHORT CIRCUIT FLUX (dB) SHORT CIRCUIT FLUX PER UNIT TRACK WIDTH (nWb/m) O -10 34.8 -20 - 30 40 50 80 IO0 160 200 315 400 630 000 1.25 1.6 25 3.15 5 6.3 IO 12.5 31.5 63 125 250 500 Ik 2k 4k 8 I: 16k FREQUENCY IN HERTZ Figure 1 - Short circuit tape flux per unit track width1 and relative le

22、vel vs frequency for audio 1 record Table 1 - Flux and flux level versus frequency Relativem I el Lp) $Y ( Frequency Flux (a) Hz nWb/m)_._. dB - 63 57.4 - 5.6 80 50.2 - 6.8 1 O0 45.5 - 7.7 125 42.2 - 8.3 160 39.7 - 8.9 200 38.2 - 9.2 250 37.2 - 9.4 31 5 36.6 - 9.6 400 36.1 - 9.7 500 35.8 - 9.8 630 3

23、5.5 - 9.8 800 35.2 - 9.9 1 O00 34.8 -1 0.0 1250 34.3 -1 CI. 1 1600 33.5 -1 0.3 2000 32.5 -1 Cl.6 2500 31.1 -1 1 .o 31 50 29.1 -11.6 4000 26.5 -12.4 5000 23.8 -13.3 6300 20.7 -14.5 8000 17.4 -16.0 10 O00 14.6 -17.6 12 500 12.0 -1 9.2 16 O00 9.6 -21.2 ) Calculated using the equation a = 110 antilog10

24、(LQ / 20). *) Calculated using the equation given in 4.2.2. _. Page 3 of 6 pages SMPTE LL 95 8357403 OOOL880 TBT ANSI/SMPTE 11-1995 4.2.3 Flux level variation 5.1.4 Distortion The short circuit flux recorded on the tape at each frequency up to and including 10 kHz shall be within f 0.5 dB of the val

25、ue specified in 4.2.2. Above 1 O kHz, the tolerance shall be increased to 2 1 dB. The toler- ance may be extended to f 2 dB, provided that a The total harmonic distortion of this section when reproduced shall not exceed 5%. 5.1.5 Duration calibration chart is supplied with the test tape by the manuf

26、acturer. The minute. duration of this section shall be one 4.2.4 Test calibration 5.2 Frequency response section The calibration Values in decibels furnished with the Recorded on audio 2 record, this section is to be used test tape shall represent the levels to be added particular test tape is repro

27、duced. With the addition of these values, the output level of the reproducer will be that which would have resulted if the short circuit flux on the test tape at a given frequency had been exactly as specified in 4.2.2 and shown in table 1 I 4.2.5 Duration to calibrate the frequency response of the

28、audio 2 (cue recorder. 5.2.1 Frequencies The following test segment frequencies (in hertz) shall be recorded in the order given: algebraically to the reproducer Output level when the track) system of a quadruplex video magnetic tape The duration of frequency response test segments 1 O00 (reference)

29、shall be approximately 1 O seconds. 63 125 4000 8000 10 O00 5 Audio 2 record test sections 250 12 500 500 1 O00 2000 16 O00 1 O00 (reference) 5.1 Audio operating level section The frequency of each recording shall be within f 2% exactly 7.5 in/s (190.5 mmls). This Section is used t0 calibrate the Se

30、IlSitiVit) Of the of its specified value when the tape is reproduced at audio (cue) reproducing system. 5.1.1 Frequency 5.2.2 Tape flux level vs frequency 5.1.2 Tape flux per unit track width The audio operating level test recording has an rms L,.p (9 re 260 nWb/m = - 9.8 + 10 logio l + (Ff12 / l +

31、(f/Fh)* dB1 short circuit tape flux per unit track width of 260 nWb/m * 7 nWb/m. where La is the relative tape flux level; f is the frequency at which the response is being computed; Fi is the low-frequency transition frequency, 80 Hz; and Fh is the high-frequency transition frequency, 4500 Hz. A gr

32、aph of this equation is shown in figure 2. The values of the tape flux and relative flux level are given in table 2. 5.1.3 Flux level variation The flux level variation during the length of tone shall fall within an envelope whose total width is 0.5 dB. Page 4 of 6 pagas ANSI/SMPTE 11-1995 RELATIVE

33、LEVEL OF SHORT CIRCUIT FLJX PER SHORT CIRCUIT FLUX (dB1 UNIT TRACK WIDTH (nWb/m) 260.0 164.0 130.3 f-a2.2 103.5 26 .O III11111111 III IIIII I, 11111111111111111111111 80 i00 160 200 315 400 630 800 1.25 1.6 2.5 3.15 5 6.3 IO 12.5 63 125 250 500 Ik 2k 4k 8k 16k FREQUENCY IN HERTZ Figure 2 - Short cir

34、cuit tape flux per unit track width and relative level vs frequency for audio 2 record Table 2 - Flux and flux level versus frequency Frequency Flux () Relative lgyel (LQ) Hz nWb/m dB 63 135.7 - 5.6 80 1 O0 125 160 200 250 31 5 400 500 630 800 1 O00 1250 1600 2000 2500 31 50 4000 5000 6300 8000 10 O

35、00 12 500 16 O00 118.7 107.5 99.6 93.8 90.4 88.0 86.4 85.3 83.8 83.1 82.2 81 .O 79.2 76.7 73.4 68.8 62.7 56.2 48.8 41.2 34.4 28.4 22.7 84.5 - 6.8 - 7.7 - 8.3 - 8.9 - 9.2 - 9.4 - 9.6 - 9.7 - 9.8 - 9.8 - 9.9 -10.0 -10.1 -10.3 -10.6 -11.0 -1 1.6 -12.4 - 13.3 - 14.5 -16.0 -17.6 - 19.2 -21.2 Calculated u

36、sing the equation = 260 antilog10 (La / 20). *) Calculated using the equation given in 5.2.2. SMPTE 33 95 8357403 0003882 852 ANSUSYPTE 11-1995 5.2.3 Flux level variation The short circuit flux recorded on the tape at each frequency, up to and including 10 kHz, shall be within * 0.5 dB of the value

37、specified in 5.2.2. Above 1 O kHz, the tolerance shall be increased to * 1 dB. The toler- ance may be extended to i 2 dB, provided that a calibration chart is supplied with the test tape by the manufacturer. recording. Journal of the SMPTE 78(6): 457-472; June 1969. Lovick, R.C.; Bartow, R.E.; and S

38、cheg, R.F. Record- ing and calibration of super-8 magnetic reproducer test films. Journal of the SMPTE 78(6): 473-481 ; June 1969. 6.2 Flux level variation 6 Calibration 6.1 Short circuit tape flux All flux level variations shall be measured with a meter or graphic level recorder which has a full-wa

39、ve recti- fied average measurement law and the dynamics of the standard volume indicator (vu meter), as specified in ANSI,IEEE ,52. The short circuit tape flux on the test tape shall be determined by means of the calibrated short-gap ferromagnetic core reproducer technique. This tech- nique is descr

40、ibed in the following references: American National Standard Method of Measuring Recorded Flux of Magnetic Sound Records at Medium Wavelengths, ANSI S4.6-1982 (R1992). 6.3 Weighted peak flutter weighted peak flutter shall be measured in accord- ance with ANSI s4.3. McKnight, J.G. Flux and flUX-fWuenCY response measurements and standardization in magnetic NOTE -A guide to proper usage and an explanation of the calibration techniques shall be supplied with each test tape. Page 6 of 6 pages