Icom IC-751A Service Manual page 34

VFO A—VFOB
VFO A is in use.
VFO B is in use. VFOB—-VFOA
(10) Y2— DB6-DB7
(DISPLAY - MEMORY/MEMORY ~— VFO)
This matrix is for memory write and the memory data
transfer by the [WRITE] and [MPVFO] SWITCHES. When
combined with the [FUNCTION] SWITCH the data in the
displayed memory channel is cleared and the channel is
blanked.
VFO Aor WRITE Transfers the VFO frequency
VFO Bis to the selected memory channel.
in use M > VEO Transfers the selected memory
channel frequency to the VFO.
MEMORY WRITE Transfers the displayed frequency
CHANNEL to the selected memory channel...
MODE is :
in use M Pb VEO Transfers the displayed frequency
to the VFO previously used.
(11) Y3— DBO0-DB3 (HAM BAND)
This matrix switches the TUNING CONTROL to a band
selected by the [BAND] SWITCH. When the [HAM/GENE]
SWITCH is at the [GENE] position the frequency is changed
in 1MHz increments: :
This matrix selects the operation mode when combined with
a mode switch or the [FUNCTION] SWITCH. The display
frequency is shifted depending on the selected operation
mode as shown in the table below.
1,900.0
3,550.0
7,050.0
10,050.0
14,050.0
18,050.0
21,050.0
24,550.0
28,050.0
(12) Y4-- DB2 (AM)
(13) Y4— DB3 (CW)
(14) Y4 — DB4 (RTTY)
(15) Y4— DBS5 (SSB)
FREQUENCY DIFFERENCES IN VARIOUS MODES
7.047.0 7.050.0
7.049.4
600Hz
USB cw LSB
RTTY AM
(MARK) FM
Fig. 20
(16) Y6 —- DBO (MODE SEARCH)
This matrix is for the SELECTED MODE SCAN and is
activated by the [MODE-S] SWITCH. Only the memory
channels with the desired operation mode are selected in
this scan.
(17) Y6 — DB1 (PITCH CLEAR)
This matrix sets the frequency increment to 1kHz in all
modes by the [TS] (Tuning Step) SWITCH. When the [TS]
SWITCH is ON, the matrix at Y7-DB¢4 is also turned ON.
(18) Y6 — DB2 (DFS)
This matrix is for dial function selection as set by the [DFS]
SWITCH. Refer to the following table.
VFO Aor Changes displayed | Changes displayed
VFOB frequency memory channel
is in use number
MEMORY Selects a memory Changes displayed
CHANNEL | channel (its frequen-; frequency
MODE cy is displayed)
(19) Y6 — DB6 (RSW)
This matrix resets RIT data or outputs N-data. IC4(a), |C-4(b),
IC5(a), 1C5(b), 1C5(d), R17 and D16 are for the RSW input
circuit.
OFF | OFF RX OFF @ When RSW MATRIX is
TX OFF OFF, the operating fre-
quency becomes the dis-
RX OFF played frequency plus
ON | OFF tx | on RIT/ATX Af frequency.
e When RSW MATRIX is
RX ON ON, the operating fre-
OFF | ON TX OFF quency is the displayed
frequency.
RX°| OFF
ON | ON
TX OFF
(20) Y6 — DB7 (SEND)
This matrix is for transmit mode recognition for stopping
scanning operations.
(21) Y7 — DBO (REMOTE RP)
This matrix is for remote-control read pulses.
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