TS-5700
8
CIRCUIT D ES CRIPTION
•
I F Filter Ratings (TX-RX U n it)
Item
XF1 : L71-0401-05
N o m i n a l center fre q u e n cy
73 0 5 M H z
Pass bandwidth
± 7 . 5 k H z or more at 3dB
Atte n uation bandwidth
±30kHz or less at 40dB
R i p p l e
1 . 0 d B or less
I n se rtion loss
3 O d B or less
G u a ra nteed atte n uation
7 0 d B o r more at fo+(500 - 1 OOOkHz)
7 0 d B o r more at fo-(200 - 1 OOOkHz)
Center freq u e n cy deviation
With i n ± 1 . 5 k H z at 3dB
Term i n a t i n g i m pedance
2 kQ± 1 0 %
Item
CF1 : L72-0372-05
N o m i n a l center freq u e n cy
455kHz
Pass bandwidth
±6kHz o r more at 6d B
Atte n u ation b a n dwidth
± 1 3 k H z or less at 50d B
R i pp l e
3d B o r less (With i n 455± 4 k H z)
I n se rtion loss
6.0dB o r less
G u a ra nteed atte n uation
3 5 d B o r more at fo± 1 O O H z
Term i n a t i n g i m pedance
2 kQ
•
Receiver Front-End
The signal input to the TX-RX unit passes through
the attenuator switching circuit and the 30MHz low
pass filter. The signal of less than 1.705MHz passes
through the low-pass filter and about-20dB attenuator
(the attenuator can be disabled by using a short
jumper). The signal of 1.705MHz or higher passes
through the short wave broadcast band trap (E type
only) and medium wave broadcast band trap and
passes through the nine-part band-pass filter. A PIN
diode for switching band-pass filters is used at the in
put side to improve inter modulation.
RFA2
(21.5MHz
PRE
ON :
LI
XF2: L71-0266-05
XF3: L71-0208-15
8830 k H z
883 0 k H z
± 3 . 0 k H z o r more at 6dB
± 1 .2kHz or more at 6dB
± 1 3 k H z o r less at 50d B
± 1 . 5 k H z or less at 2 0 d B
± 1 6 k H z or l e s s at 60d B
± 2 . 2 k H z or less at 60d B
± 3 . 0 k H z or less at SOd B
1 . 0 d B or less
2 . 0d B or less
1 . 5dB o r less
6.0dB o r less
7 0 d B o r more at fo± 1 M H z
80d B or more at fo± 1 M H z
-
Wit h i n ± 1 50 H z at 6 d B
1 850Q
II
2 p F
600Q± 5 %
II
1 5 p F± 5 %
CF500, 501 : L72-0351-05
8830 k H z
± 50 k H z o r m o r e at 3 d B
3 5 d B or more at +455kHz
45dB o r more at + 9 1 O k H z
1 . O d B or less
6 O d B o r less
-
330Q
If PRE-AMP is off, 030 and 032 turn on, and the
signal passing through each band-pass filter goes to
the quad-balance type first mixer by 05 to 08:
2SK520x4. If PRE-AMP is on, 043 and 045 turn on,
and the signal of less than 21.5MHz passes through
parallel amplifier 017, 018: 2SK520x2. This amplifier
uses NFB to suppress the low-band gain and improve
strong signal input characteristics. When the fre
quency is 22MHz or higher, 051 and 052 turn on, sen
sitivity-oriented MOS FET amplifier 025: 3SK131 1s
selected.
RFA1
(-21.5MHz
PRE
ON :
LI
L01
IF
73.05MHz
Fi g.
6
Receiver front-end block diagram
