Promax TV EXPLORER II, Руководство пользователя

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USER’S MANUAL. TV EXPLORER II/II+
12/2013 Page 51
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As well as the video carrier / noise level ratio ( C/N ) (40.1 dB in previous figure), the
frequency or channel (depending on the tuning mode selected) and the level of the video
carrier and video/audio ratio are also shown. When representing the spectrum by means
of pressing [13] key, the NOISE cursor is automatically positioned to a side of the
carrier tuned. That is, the cursor will indicate the point where the value of the noise is
lower, whenever the C/N(AUTO) option is selected from the PREFERENCES [22]
menu. If the C/N(MANUAL) option has been activated the frequency where noise level
will be measured will correspond to the position of the vertical discontinuous green-
coloured cursor that appears in the spectrum graph [13].
In order to modify this frequency, press the measurement configuration [17]
key, to accede to the CONFIGURATION menu. By turning the rotary selector [1], locate
the NOISE cursor on the position of the marker using
NOISE FREQ. TO MARKER
option
(see section “ 5.16.1 Markers ”) or directly enter the value of the new noise frequency by
means of
NOISE FREQ
option.
70
60
50
40
30
FREQ:
C/N REF:
43 CH: SPAN: 32 MHz
650.00 MHz
16.5 dB
Figure 27.- NOISE cursor. C/N (MANUAL)
When measuring channels in the satellite band or digital channels, to measure the
C/N ratio correctly, the bandwidth of the channel must be defined previously, using the
Channel BW option on the Measurements Configuration menu that appears when
pressing the [17] key.