Sony CRF-150 - Block Diagram

CRF-150
Limiter This diode clips the positive
D301 Peak of ac signal voltage devel
oped
at
the
collector
of
0305.
Fm
if
0305
amplifies
10.7
MHz
fm
+f
amplifier.
signal,
Also,
0305
produces
a
455 kHz am Ы signal on its
Am 2nd mixer conector,
0305
Power
Supply
Fig
16
Selectivity
selection
circuit
Тһе CRF-150 uses a 4-pin ac cord for its power Bs Asi
supply and has a powerin jack for a house current
100V,
117V,
220V
and
240V
(for
USA
model
117V
VOLUME
control
The
level
of
signal
applied
to
only). However, by using the SONY DCC-2A Car VR601 the power amplifier is deter-
tery
Cord
or
standard
flashlight
batteries
(six
size
mined
by
the
setting
of
VR601.
"D" cells), the CRF-150 can be operated away from
ап ас power outlet. Though diode 0502 prevents Amplifier ‘Transistor Q401 amplifies the
а
reverse
current
flow
through
the
batteries
when
0401
audio
signal
supplied
by
using а house current or car battery, it is better to VOLUME control VR601.
remove the flashlight batteries if they will not be
used for a while, Audio driver These direct-coupled stages
0402, 0403 amplify the audio signal supplied
by TREBLE control VR602
and BASS control VR603,
Sensitivity Selector
‘The stage selectivity is obtained by using a Power amplifier This stage uses an OTL (output
ceramic filter (CF304) as а frequency-selective 0404, 0406 transformerless) push-pull class-B
by-pass centered at 455 kHz. This gives transistor amplifier, Thermistors CS401
Q304 a high gain at 455 kHz by preventing emitter and CS402 temperaturecompen-
degeneration of the signal at this frequency. Ву sate the base bias of Q404 and
connecting capacitor C372 in parallel with filter 0405.
СЕЗ04 (See Fig. 1-6), the BROAD selectivity band- Negative feedback from the out-
width is obtained. When the SHARP position is set, put of 0404 and 0405 to the
the bandwidth becomes narrow. However, greater emitter of 0403 improves the
sensitivity with less noise is obtained and a weak frequency response and reduces
signal can easily be heard, distortion,
1-4. BLOCK DIAGRAM
е Fig 17