1、SMPTE 8 95 8357403 000393b 853 W SMPTE STANDARD for Video Recording - Quadru plex Recorders Operating at 15 in/s - Audio Level and Multifrequency Test Tape SMPTE 8-1995 Revision of ANSIEMPTE 8-1989 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 15 in/s (381 mm/s). The tape shall be used on recorders, operating in accordance with ANSVSMPTE 3. The operating level and frequency
3、response for audio 2 record are specified in SMPTE RP 102. Page 1 of 6 pages ANSVSMPTE 4-1 995, Television Analog Recording - 2-in Magnetic Tape for Quadruplex Recording - Speed ANSIlSMPTE 6-1 993, Video Recording - 2-in Quad- ruplex Tape - Video, Audio and Tracking-Control Records ANSVIEEE 152-1992
4、, Audio Program Level Measure- ment SMPTE RP 16-1993, Specifications of Tracking- Control Record for 2-in Quadru plex Video Magnetic Tape Recordings 2 Normative references SMPTE RP 102-1 991, Frequency Response and Operating Level of Recorders and Reproducers for T Operating at 15 and 7-5 in/s The f
5、ollowing standards COntainS PrOViSionS which, Audio 2 Record for 2-in Quadruplex Video Magnetic 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 revision, and parties to agreements base
6、d on this G specifications standard are encouraged to investigate the possibility of applying the most recent edition of the standards 3., Dimensions of records indicated below. The dimensions of pertinent records constituting this test tape shall conform to ANSI/SMPTE 6. 3.2 Tape speed The nominal
7、linear speed of this test tape shall be 15 in/s (381 mmls) in accordance with ANSI/SMPTE 4. ANSI S4.3-1982 (R1992), Method for Measurement of Weighted Peak Flutter of Sound Recording and Reproducing Equipment ANSI S4.6-1982 (R1992), Method of Measuring Recorded Flux of Magnetic Sound Records at Medi
8、um Wavelengths 3.3 Stock ANSI/SMPTE 1-1 990, Video Recording - 2-in Magnetic Recording Tape ANSI/SMPTE 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 sections shall be reco
9、rded on transversely oriented television magnetic recording tape, the dimensions of which are specified in ANSI/SMPTE 1. 3.4 Videosignal A color black video signal may be recorded. CAUTION NOTICE This Standard may be revised or withdrawn at any time. The procedures of the Standard Developer require
10、that action be taken lo 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 writing the Standard Developer Printed in USA. Copyright O 1995 by THE SOCIETY OF L America
11、n Nalional Standard MOTION PICTURE AND TELEVISION ENGINEERS 595 W Haitcdale Ave , White Plains. NY 10607 (914) 761-llM) Approved February 13,1995 SMPTE 8 75 83574011 00011937 79T M ANSI/SMPTE 8-1995 3.5 Tracking-control signal A tracking- control signal, conforming to that specified in SMPTE RP 16,
12、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 operating level test ton
13、es 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. 4.1.4 Distortion The total harmonic distortion of
14、 this section when reproduced shall not exceed 2%. 4.1.5 Duration The minimum duration of this section shall 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
15、magnetic tape recorder. 4.2.1 Frequencies 3.7 Flutter The weighted peak 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“ 2 3 to the reference edge of the tape. 4 Audio 1 record test sections 4.1 Audio operating level section Thi
16、s section is used to calibrate the sensitivity of the audio reproducing system. 4.1.1 Frequency The frequency of the recording shall be 1 O00 Hz t 2% when the tape is reproduced at exactly 15 in/s (381 m m/s) . 4.1.2 Tape flux per unit track width The audio operating level test recording has an rms
17、short circuit tape flux per unit track width of 11 O nWb/m +: 3nWb/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. The following test segment frequencies (in hertz) shall be recorded in the order given: 1
18、 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 t 2% of its specified value when the tape is reproduced at exactly 15 in/s (381 mmls). 4.2.2 Tape flux level vs frequency The relative short circuit tape flux l
19、evel versus frequency expressed in decibels shall be as given by the following equation: LQ (f) re 110 nWb/m = 0.2 + 10 logio l + (Fi/fj2 / l + (f/Fh)2 1 dBl where LQ is the relative tape flux level; f is the frequency at which the response is being computed; Fi is the low-frequency transition frequ
20、ency, 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 8 95 m 8357903 0003938 b2b II RELATIVE LEVEL OF SHORT CIRCUIT FLUX (d) ANSIISMPTE
21、8-1995 SHORT CIRCU17 FLUX PER UNIT TRACK WIDTH (nWb/m) f 10 O -10 -20 40 50 80 100 160 200 315 400 630 800 125 1.6 25 3.15 5 6.3 IO 12.5 315 63 125 250 500 Ik 2k 4k Bk 16k FREPUENCY IN HERTZ Figure 1 - Short circuit tape flux per unit track width and relative level vs frequency for audio 1 record Ta
22、ble 1 - Flux and flux level versus freauencv - iio.0 Frequency Flux (I) Relativt? le el (LQ) Hz nWb/m - . clB 2y 63 80 1 O0 125 160 200 250 31 5 400 500 630 800 1 O00 1250 1600 2000 2500 3150 4000 5000 6300 8000 10 O00 12 500 16 O00 181.5 158.8 143.8 133.3 125.4 120.9 11 7.7 115.6 114.1 113.1 112.2
23、111.2 110.0 108.4 105.9 02.7 98.3 92.0 83.9 75.1 65.3 55.1 46.1 38.1 + 4.4 + 3.2 + 2.3 + 1.7 t 1.1 + 0.8 t 0.6 + 0.4 + 0.3 + 0.2 + 0.2 + 0.1 0.0 - 0.1 - 0.3 - 0.6 - 1.0 - 1.6 - 2.4 - 3.3 - 4.5 - 6.0 - 7.6 - 9.2 ) Calculated using the equation Q = 110 antilog10 (La / 20) *) Calculated using the equat
24、ion Wen in 4.2.2. , Page 3 of 6 pages SMPTE A 95 A357403 00011939 562 M ANSVSMPTE 8-1995 4.2.3 Flux level variation The short circuit flux recorded on the tape at each frequency shall be within 2 0.5 dB of the value specified in 4.2.2. The tolerance of i- 0.5 dB may be extended to 2 dB, provided tha
25、t a calibration chart is supplied with the test tape by the manu- fact u rer. 4.2.4 Test calibration The calibration values in decibels furnished with the test tape shall represent the levels to be added algebraically to the reproducer output level when the particular test tape is reproduced. With t
26、he 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. 5.1.4 Distortion The total harmonic distortion of this section when repr
27、oduced shall not exceed 5%. 5.1.5 Duration The minimum duration of this section shall be one minute. 5.2 Frequency response section Recorded on audio 2 record, this section is to be used to calibrate the frequency response of the audio 2 (cue track) system of a quadruplex video magnetic tape recorde
28、r. 5.2.1 Frequencies The following test segment frequencies (in hertz) shall be recorded in the order given: 4.2.5 Duration The duration of frequency response test segments shall be approximately 1 O seconds. 5 Audio 2 record test sections 5.1 Audio operating level section This section is used to ca
29、librate the sensitivity of the audio (cue) reproducing system. 5.1.1 Frequency The frequency of the recording shall be 1 O00 Hz 2 2% when the tape is reproduced at exactly 15 in/s (381 m m/s) . 5.1.2 Tape flux per unit track width The audio operating level test recording has an rms short circuit tap
30、e flux per unit track width of 260 nWb/m 2 7 nWb/m. 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. 1 O00 (reference) 4000 63 8000 125 10 O00 250 12 500 500 16 O00 1 O00 1 O00 (reference) 2000 The frequency of e
31、ach recording shall be within f 2% of its specified value when the tape is reproduced at exactly 15 ids (381 mm/s). 5.2.2 Tape flux level vs frequency The relative short circuit tape flux level versus frequency expressed in decibels shall be as given by the following equation: LQ (9 re 260 nWb/m = -
32、 9.8 + 1 O logi o l - (Fi/Q2 / l + (f/Fh)* 1 dBl 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 graph of this equation is shown in
33、 figure 2. The values of the tape flux and relative flux level are given in table 2. Page 4 of 6 pages SMPTE 8 95 8357401 0001940 2814 H ANSI/SMPTE 8-1995 RELATIVE LEVEL OF SHORT CIRCUIT FLUX (dB) SHORT CIRCUIT FLUX PER UNIT TRACK WIDTH (nWb/rn) O -10 -20 .30 260 O 206 5 164 O 130.3 103 .5 -82 2 65.
34、3 51 .9 41 .2 32.7 26.0 1 80 i00 160 200 315 400 630 800 1.25 1.6 2.5 3.15 5 6.3 IO I23 63 125 250 500 Ik 2k 4k 8k 16k FREQUENCY IN HERTZ Figure 2 - Short circuit tape flux per unit track width and relative level vs frequency for audio 2 record Table 2 - Flux and flux level versus frequency Frequenc
35、y Hz Flux (j) Relative ie2yei (LQ) nWblm dB 63 135.7 - 5.6 80 1 I 8.7 - 6.8 1 O0 107.5 - 7.7 125 99.6 - 8.3 160 93.8 - 8.9 200 90.4 - 9.2 250 88.0 - 9.4 31 5 86.4 - 9.6 400 85.3 - 9.7 500 84.5 - 9.8 630 83.8 - 9.8 800 83.1 - 9.9 1 O00 82.2 -1 0.0 1250 81 .O -10.1 1600 79.2 -1 0.3 2000 76.7 -1 0.6 25
36、00 73.4 -1 1 .o 31 50 68.8 -1 1.6 4000 62.7 -1 2.4 5000 56.2 -1 3.3 6300 48.8 -1 4.5 8000 41.2 -1 6.0 10 O00 34.4 -17.6 12 500 28.4 -19.2 22.7 -21.2 16 O00 -. ) Calculated using the equation a = 260 antiloglo (La / 20) *) Calculated usina the eauation aiven in 5.2.2. J Page 5 of 6 pages SMPTE 8 i5 8
37、357403 OOOLi43 310 D ANCI/SMPTE 8-1995 5.2.3 Flux level variation The short circuit flux recorded on the tape at each frequency, up to and including 1 O kHz, shall be within I 0.5 dB of the value specified in 5.2.2. Above 10 kHz, the tolerance shall be increased to I 1 dB. The toler- ance may be ext
38、ended to I 2 dB, provided that a calibration chart is supplied with the test tape by the manufacturer. 6 Calibration 6.1 Short circuit tape flux 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- n
39、ique is described in the following references: American National Standard Method of Measuring Recorded Flux of Magnetic Sound Records at Medium Wavelengths, ANSI S4.6-1982 (R1992). McKnight, J.G. Flux and flux-frequency response measurements and standardization in magnetic recording. Journal of the
40、SMPTE 78(6): 457-472; June 1969. Lovick, R.C.; Bartow, R.E.; and Scheg, R.F. Recording and calibration of super-8 magnetic reproducer test films. Journal of the SMPTE 78(6): 473-481; June 1969. 6.2 Flux level variation All flux level variations shall be measured with a meter or graphic level recorde
41、r which has a full-wave recti- fied average measurement law and the dynamics of the standard volume indicator (vu meter), as specified in ANSI/IEEE 152. 6.3 Weighted peak flutter Weighted peak flutter shall be measured in accord- ance with ANSI S4.3. 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
