Icom IC-551D Instruction Manual page 34

A:P.B. TUNE centered
©
® Output Signals ® Pass band of Output Signals
of MAIN unit 21 of Mixer В
СЕ тагт opi ad где бара
(ар (KHz) 1075, (Кн) (2015 (KHz)
~ \MHz E | MHz
Turning the Pass Band Tuning control fully clockwise, the VXO frequency will become 19.7630
MHz (19.7615+1.5KHz). When mixed with the incomming 9.0115MHz signals, the resultant
frequencies become 10.7503MHz to 10.7527MHz. Since the upper frequency pass band limit of
the filter is 10.7512MHz, not all the signals will be passed by the filter. Only the signals between
10.7503MHz and 10.7512MHz, the upper limit, will be passed. As you can see, the pass band has
been narrowed to 900Н2 to one side of the center frequency of the filter. Therefore, all signals
outside the 10.7503MHz to 10.7512MHz range will not pass through the filter.
В: P.B. TUNE fully clockwise | |
Pass Вапа of (8 ырш Signals of ©
Output ЕЙ: їхег А Output Signals
Signals of N ids of Mixer B
MAIN unit [| ^1
Eq
КЕ
Вай
14
MEE.
-—9 —1 0 ae. —2 -1 0 ЗРЕО а —2— 0-2
9 0115 (KHz) Gs (KHz) Cae (KHz) |
ae MHz MHz
By turning the Pass Band Tuning control in the fully counterclockwise position, the V XO frequency
becomes 19.760MHz. Тһе 10.750MHz signals from the mixer A will be from 10.7497MHz to
10.7473MHz. Again with the 10.7512MHz to 10.7448MHz pass band width of the filter, not all
signals will be passed. Only those between 10.749MHz to 10.7488MHz will be passed. Again,
the pass band has been narrowed to 900Hz and offset to the opposite side of the center frequency
of the crystal filter.
. C:P.B. TUNE fully counterclockwise
® Output Signal Pass band ©
Output 9f Mixer А of FI1 Output Signals
Signals of + of Mixer В
MAIN unit
|
]
1
1
1
Li
І
i
-2-10 +1 +2 -3-2-1 0 +1 42 еи Јевреја
Gay (Кнг) (72 (Кнг) е (KHz)
MHz MHz MHz
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