B&K Precision 1249B - Manual - Manual (Page 19)

19
CONTROLS AND INDICATORS (CONT.)
approximately 1KHz) is included in the signal at the IF/RF
output jack. When this switch is disengaged, no sound carrier
is included in the signal.
9. IF/RF Switch. Sets modulated output signal (at the IF/RF
output jack) to rf or i-f frequency. When this switch is engaged,
the signal at the IF/RF jack is at i-f signal frequency
(45.75MHz) and the CH 4/CH 3 switch has no effect. When
disengaged, the signal at the IF/RF jack is at rf signal frequency
(61.25MHz for CH 3 or 67.25MHz for CH 4).
10. CH 4/CH 3 Switch. Works in conjunction with rf position of
IFIRF switch. Sets rf output carrier frequency to correspond to
CH 4 or CH 3. When the IF/RF switch is in the rf position
(disengaged) and this switch is disengaged (in the CH 3
position), the output signal at the IF/RF jack corresponds to TV
channel 3 (61.25MHz). When the IF/RF switch is in the RF
position (disengaged) and this switch is engaged (in the CH 4
position), the output signal at the IF/RF jack corresponds to TV
channel 4 (67.25MHz). When the IF/RF switch is in the IF
position (engaged), this switch has no effect on the output.
11. COMPOSITE VIDEO LEVEL Control. Adjusts level and
polarity of composite video signal at COMPOSITE VIDEO
output jack. Counterclockwise rotation produces a composite
video signal with negative going sync pulses (standard signal).
Full counterclockwise rotation of this control provides
maximum output signal with a calibrated level of 1Vp-p into
75
Ω. Amplitude reduces to minimum at mid-point. Further
clockwise rotation reverses polarity (positive going sync) and
progressively increases amplitude. Full clockwise rotation of
this control provides an output signal with a level of
approximately 1Vp-p into 75
Ω.
12. COMPOSITE VIDEO Jack. Provides a video output for signal
substitution directly into the video circuits of a television receiver
and for testing video recorders.
13. IF/RF Jack. Provides approximately 10mV rms (into 75
Ω) rf
envelope modulated by composite video. Output carrier
frequency can be set to 45.75MHz (IF), 61.25MHz (CH 3) or
67.25MHz (CH 4) by the CH 4/CH 3 and IF/RF switches.
14. 30Hz Jack. Provides a 30Hz square wave TTL level output
useful for troubleshooting video recorders.
15. COMPosite SYNC Jack. Provides both horizontal and vertical
sync pulses for external use such as monitors requiring separate
composite sync or sync trigger for an oscilloscope. Sync pulse
is negative polarity. Output impedance is 75
Ω, level is TTL
compatible.
16. SYNC Vs Jack. Provides vertical sync pulses for external use
such as vertical sync for RGB monitors or sync trigger for an
oscilloscope. Sync is positive polarity. Output impedance is
75
Ω. Level is TTL compatible.
17. SYNC Hs Jack. Provides horizontal sync pulses for external
use such as horizontal sync for RGB monitors or sync trigger
for an oscilloscope. Sync pulse is positive polarity. Output
impedance is 75
Ω. level is TTL compatible.
18. B Jack. Provides blue output signal for use with RGB monitors.
Output impedance is 75
Ω and output level is switch selectable
(using the RGB TTL/LOW switch).