Q1. Vertical blanking appears on the monitor
Q2. Picture on the monitor screen is movable up or down by switching TBC ON mode to BYPASS mode.
Q3. Although Time Code DATA value was preset; DATA value shown in the counter is not switched.
Q4. When an EDIT switch (ASSEMBLE or INSERT) is turned ON during playback, picture on the monitor screen moves down.
Q5. A gray band appears on the monitor screen in STILL mode.
Q6. Time Code value is not moveable in variable-speed playback.
Q7. Upon beginning playback, short noise occasionally enters (slow build up). Or, the picture moves horizontally (H shift occurs).
Q8. Playback time Code value shown in the counter cannot be reset.
Q9. The function KEY switch of the equipment set is not operable.
Q10. SCH and Color Framing

The Betacam-2000 Pro Series has been developed on the basis of the Betacam (BVW series) with the same format.
Therefore, there are several complicated or important functions, which are described as follows in questions and
answers. Before you decide a trouble if any as an equipment failure, check it once again referring to the
following description.

(1) E-E Mode

Q: V blanking appears on the monitor screen.

A1: If the same phenomenon does not appear in the E-E BYPASS mode, it may be assumed there is no Ref input signal. Enter a correct Ref signal at the input Ref terminal. If such a Ref signal is not available, enter an input VIDEO signal at the Ref terminal by a through-connection.

A2: It can be assumed that the phases of the VIDEO input signal and the Ref input signal are different. With the PVW-2000 PRO Series (studio equipment), the TBC is mounted and newly generates SYNC and burst signals and replaces those in the VIDEO OUT signal output with new ones. These SYNC and burst signals are generated based on the timing of the input Ref signal, so you have to coincide its phase with that of the input VIDEO signal.

Q: Picture on the monitor screen is movable up or down by switching TBC ON mode to BYPASS mode.

A: Input VIDEO signal is 8H delayed since it is once written in the MEMORY. Therefore, in the TBC ON mode, signal output is delayed by 8H from that in the BYPASS mode. This occurs in the BVW-SP series.

Q: Although Time Code DATA value was preset; DATA value shown in the counter is not switched.

A: The Time Code shown in the counter represents the final Reader value, which is maintained even after the DATA is preset. In order to check and execute the preset value, press the REC button to effect REC MODE, thereby the counter indicates the preset value.

(2) Playback mode

Q: When an EDIT switch (ASSEMBLE or INSERT) is turned ON during playback, picture on the monitor screen moves down.

A: Because the Ref for the Servo block is switched from PLAY mode to REC mode. Normally VIDEO signal is transmitted through the TBC while being 8H delayed. Therefore, in playback mode, signal DELAY in the VIDEO output is eliminated by letting the servo Ref lead 8H to detect playback signal earlier. However, when the EDIT switch is turned ON, the timing of servo Ref is changed over the timing in REC (E-E mode). As a result, with the EDIT switch turned ON, the VIDEO output is delayed by 8H.

Q: A gray band appears on the monitor screen in STILL mode.

A: In the Betacam, Y and C signals are recorded and played back by different heads in order to ensure azimuth recording to prevent interference between Y and C signals. In STILL mode the VIDEO head plays back a zone between two tracks as shown below. If the Y and C heads move over the C and Y track, respectively at that time, guard band noise (gray band) may appear.

Q: Time Code value is not moveable in variable-speed playback.

A: There are 2 types of Time Codes; one is VITC recorded in the VIDEO TRACK together with VIDEO signal and the other is LTC recorded in the TRACK special for longitudinal Time Code. It is selected by the switch on the sub control panel for either DATA to be read out. VITC DATA is no longer readable when tape speed exceeds +/- 1Ox speed or more. Therefore, at a tape speed higher than 1Ox speed, the previous DATA remains displayed. With a tape speed less than +/-1/3Ox, LTC DATA can not be read any longer. At that time, the data is compensated by the capstan FG value, while displaying mark* in the character window on the monitor.

Normally by setting the time Code select switch to AUTO mode. LTC DATA is read into the main and, in the section where the tape runs at a speed of -1/2x to +1/2x, VITC data is automatically read.

Q: Upon beginning playback, short noise occasionally enters (slow build up). Or, the picture moves horizontally (H shift occurs).

A: When the tape with composite signal recorded is played back, the symptom above takes place depending on the position of the CAPSTAN Lock switch on the equipment set.

Basic principles:
With the Betacam-SP, VISC control is performed as follows so that high quality picture is obtained in recording and playing back composite signals.

Y and C signals obtained by Y/C separation during recording contain cross color and cross luminance of which the phases coincide with each other.

Agreement or disagreement in the phases of cross color and cross luminance occurs in a probability of 50% (in NTSC) before effecting Y/C mixing during playback. In agreement, the same composite output as the input signal is obtained. However, in disagreement, frequency dipping occurs in the composite output because cross color and cross luminance component cancel each other.

To prevent frequency dipping, the phase of cross luminance (phase of the entire chroma) in the ENC (encoder) output is controlled. In detail SC (sub carrier) used for ENC is controlled by the phase of the SC used in the DEC (decoder), thereby the phase of cross luminance in the ENC output always coincides with the phase of cross color.

The SC used for this control is called VISC and mixed and recorded in the blanking part of Y signal during recording.

Functions of the CAPSTAN Lock switch (Ref is defined by 1 field SC phase 0°)

CAPSTAN Lock SW Position

CAPSTAN Lock Position

Function
FIELD
SC PHASE
*2F
1
(0°)
3
(180°)
VISC control is disabled. Frequency dipping occurs at 50% probability.
2/4F
1

(0°)
3
Phase Shift
(180° -> 0°)
VISC control is enabled (without DIP). H shift (horizontal swing) occurs at50% probability
$F
1
(0°)
VISC control is enabled. If
CAPSTAN Lock occurs first at Field 3, CAPSTAN SERVO is re locked so that locking occurs in Field 1 (SERVO is instantly disorder because of noise occurring).

* At that time, it is important that SCH of the input VIDEO is not controlled.

Q: Playback time Code value shown in the counter cannot be reset.

A: Time Code value shown in the counter cannot be reset because it represents the absolute value on the tape apart from the CTL value.

Q: The function KEY switch of the equipment set is not operable.

A: Check that the REMOTE/LOCAL switch is not set to the REMOTE side.

SCH and Color Framing

In the NTSC system, a reference sub carrier is required to demodulate chroma signal. This signal is not a continuous signal but transmitted as a burst signal of 9 cycles per horizontal synchronous signal. The phase relationship at a cross point of these horizontal synchronous signal and the sub carrier is called SCH (Sub carrier to Horizontal) phase.

The SCH phase is important particularly when video signals in 2 or more systems are dealt with in switching or editing VTR. If SCH phases of video signals do not coincide with each other, shifting or jumping of video picture may occur. Consequently, it is required to control SCH phases in the entire system.

In the NTSC system, interlacing is effected as described before. Therefore, monochrome video signal completes one cycle by 2 fields, i.e. 1 frame. However, the phase relationship between sub carrier and horizontal line completes one cycle by 4 fields, i.e. 2 frames because the sub carrier frequency is selected at an odd multiple of 1/2 of the horizontal scanning period FH. Thus, color video signal in the NTSC system completes each sequence by 4 fields. This is called 4-field sequence. Among 4 color fields, Fields 1 and 2 are defined Color Frame A while defining fields 3 and 4 as Color Frame B.

 

Notes:

1. SPECIFICATIONS APPLY TO STUOIO FACILITIES NETWORK AND TRANSMITTER CHARACTERISTICS ARE NOT INCLUDED.

2. ALL TOLERANCES AND LIMITS SHOWN IN THIS DRAWING PERMISSABLE ONLY FOR LONG TIME VARIATIONS.

3. BURST FREQUENCY SHALL BE 3579545 MHz +/- 10 Hz.


4. HORIZONTAL SCANNING FREQUENCY SHALL BE 2/455 TIMES THE BURST FREQUENCY.

5. VERTICAL SCANNING FREQUENCY SHALL BE 2/525 TIMES THE HORI ZONTAL SCANNING FREQUENCY.

6. START OF COLOR FIELDS ONE AND THREE IS DEFINED BY A WHOLE LINE BETWEEN THE FIRST EQUALIZING PULSE AND THE PRECEDING H SYNC PULSE. START OF COLOR FIELDS TWO AND FOUR DEFINED BY A HALF LINE BETWEEN THE FIRST EQUALIZING PULSE AND THE PRECEDING H PULSE. COLOR FIELD ONE IS THAT FIELD WITH POSITIVE GOING ZERO-CROSSINGS OF REFERENCE SUBCARRIER NOMINALLY COINCIDENT WITH 50% AMPLITUDE POINT OF THE LEADING EDGES OF EVEN NUMBERED HORIZONTAL SYNC PULSES.

7. THE ZERO CROSSINGS OF REFERENCE SUBCARRIER SHALL BE NOMINALLY COINCIDENT WITH THE 50% POINT OF THE LEADING EDGES OF ALL HORIZONTAL SYNC PULSES. FOR THOSE CASES WHERE THE RELATIONSHIP BETWEEN SYNC AND SUBCARRIER IS CRITICAL FOR PROGRAM INTEGRATION, THE TOLERANCE ON THIS COINCIDENCE IS +/- 45° OF REFERENCE SUBCARRIER.

8. ALL RISE TIMES AND FALL TIMES UNLESS OTHERWISE SPECIFIED ARE TO BE 0.140 uSEC +/- 0.02 uSEC MEASURED FROM TEN TO NINETY PER CENT AMPLITUDE POINTS ALL PULSE WIDTHS EXCEPT BLANKING ARE MEASURED AT FIFTY PER CENT AMPLITUDE POINT.


9. OVERSHOOT ON ALL PULSES DURING SYNC AND BLANKING (VERTICAL AND HORIZONTAL) SHALL NOT EXCEED TWO IRE UNITS ANY OTHER EXTRANEOUS SIGNALS DURING BLANKING INTERVALS SHALL NOT EXCEED TWO IRE UNITS, MEASURED OVER A bANDWIDTH OF 6 MHz.

10. BURST ENVELOPE RISE TIME IS 0.30 uSEC MEASURED BETWEEN THE TEN AND NINETY PERCENT AMPLITUDE POINTS IT SHALL HAVE THE GENERAL SHAPE SHOWN.

11. THE START OF BURST IS DEFINED BY THE ZERO CROSSING (POSITIVE OR NEGATIVE SLOPE) THAT PRECEEDS THE FIRST HALF CYCLE OF SUBCARRIER THAT IS 50% OR GREATER OF THE BURST AMPLITUDE.

12. THE END OF BURST IN DEFINED BY THE ZERO CROSSING (POSITIVE OR NEGATIVE SLOPE) THAT FOLLOWS THE LAST HALF CYCLE OF SUBCARRIER THAT IS 50% OR GREATER OF THE BURST AMPLITUDE.

13. MONOCHROME SIGNALS SHALL BE IN ACCORDANCE WITH THIS DRAWING EXCEPT THAT BURST IS OMITTED, AND FIELDS THREE AND FOUR ARE IDENTICAL TO FIELDS ONE AND TWO RESPECTIVELY.

14. REFERENCE SUBCARRIER IS A CONTINUOUS SIGNAL WHICH HAS THE SAME INSTANTANEOUS PHASE AS BURST.

15. PROGRAM OPERATiNG LEVEL WHITE IS 100 IRE, +0, -2 IRE.

16. PROGRAM OPERATING LEVEL BLACK IS 75 IRE, +/- 2.5 IRE.

17. PROGRAM OPERATING LEVEL SYNC IS 40 IRE, +/- 2 IRE.

18. PROGRAM OPERATING LEVEL BURST IS 40 IRE, +/-2 IRE.

19. BURST PEDESTAL NOT TO EXCEED +/- 2 IRE.

20. BREEZEWAY, BURST, COLOR BACK PORCH, AND SYNC TO BURST END ARE NOMINAL IN DETAIL BETWEEN YY SEE DETAIL BETWEEN ZZ FOR TOLERANCES.

21. RATIO OF AREA OF VERTICAL EOUALIZING PULSE TO SYNC PULSE SHALL BE WITHIN 45 TO 50 PER CENT.

22. THERE WILL BE A 100° REVERSAL OF PHASE WHEN VIEWING EVEN LINES ON A FOUR FIELD PRESENTATION, A FOUR FIELD PRESENTATION MEANS A DISPLAY DEVICE WHICH IS TRIGGERED BY FOUR FIELD 115 Hz) INFORMATION

THIS DRAWING CORRESPONDS TO PROPOSED RS 170A VIDEO STANDARD
COLOR TIMING DATA
1° = 776 ns
INS= 12B9°
FOR CABLE WITH 66% PROPAGATION FACTOR
1° =6035"= 503'
INS = 777B" = 64B'


Detail YY

 


Detail XX

 


Detail ZZ