1、STD-SMPTE L7M-ENGL 1998 W 8357403 0003077 800 SMPTE STANDARD for Television Analoa Recordina - 1-in Type B Helical Scan - F req u e ncy Hesponse SMPTE 17M-1998 Revision of ANSVSMPTE 17M-1992 and Operating Levei 1 Scope This standard specifies the frequency response and operating level of recorders a
2、nd reproducers for audio records for 1 -in type B helical-scan video tape record- ing. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the edition indicated was valid. All stan
3、dards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. ANSVIEEE 152-1 992, Audio Program Level Measure- ment 3 Operating levels 3.1 Recording and reproducing le
4、vel indicator The audio recording and reproducing levels of a video tape recorder shall be adjusted with a standard volume indicator, as specified in ANSMEEE 152. 3.2 Recorder operating levei When a tape record is recorded from a sinusoidal voltage having a frequency of 1 O00 Hz such that the rms sh
5、ort circuit tape flux per unit track width on the record is 100 nWb/m f 3 nWb/m of track width, the recording volume indicator shall be adjusted to deflect to its reference level (O dB) scale mark. Page 1 of 2 pages 3.3 Reproducer operating level When a tape record having an rms short circuit tape f
6、lux per unit track width of 1 O0 nWb/m and afrequency of 1000 Hz is reproduced, the reproducing volume indicator shall deflect to its reference level (O dB) scale mark. 3.4 Time constants Time constants of 15 ps (tl) and 31 80 ps (t2) shall be applied. 4 Frequency response 4.1 Recorder fluxlfrequenc
7、y response When a tape record is recorded from a constant voltage level applied to the input terminals of the recording system, the short circuit tape flux level on the record versus frequency, Lm(f), shall be as given by the following equation: where LO is the relative tape flux level; f is the fre
8、quency at which the response is being computed; Fi is the low-frequency transition frequency, 50 Hz; and Fh is the high-frequency transition frequency, 1061 O Hz. 4.2 Reproducer fiuxlfrequency response When a tape record having a short circuit tape flux level versus frequency given in 4.1 is reprodu
9、ced, the output voltage level of the reproducer versus frequency shall be constant. CopyrigM O 1998 by THE SOCIE-TY OF MOTION PICTURE ANDTELEVISION ENGINEERS 595 W. Hasdeie Ave., White Plains, NY 10607 (914) 761-1100 Approved September 1,1998 5 Trackusage 5.1 When a single program record is used, it
10、 shall be placed on the audio 1 track. 5.3 A cue signal or time and control code shall be placed on audio 3 track. 6 Program audio head phasing 5.2 When two tracks are used for stereo record- ing, the left channel shall be recorded on the audio 1 track and the right on audio 2 track. When the same signal is recorded on two tracks, the tracks shall be so phased that when reproduced with a full-track head, they will be additive. Annex A (informative) Bibliography SMPTE 15M-1998, Television Analog Recording - l-in Type B Helical Scan - Basic System Parameters Page 2 oi 2 pages
