 |
|||
|
|
|||
|
Page Title:
Section V. THEORY OF TUNING UNIT 3 |
|
||
| ||||||||||
|
|  Section V. THEORY OF TUNING UNIT 3
42. Block Diagram of Tuning Unit 3
of 42 mc; therefore, all other frequencies
a r e suppressed. The difference frequency
The block diagram for tuning unit 3 is
o f 42 mc is applied to cascode driver-
s h o w n in figure 27. For complete circuit
a m p l i f i e r V403.
details, refer to figure 101.
d. 42-Mc If. Preamplifier. T h e 4 2 - m c
a. Rf Amplifier V401. Rf amplifier
i f . preamplifier consists of three stages.
V 4 0 1 is a low-noise amplifier. It ampli-
(1) C a s c o d e Amplifier V403. C a s c o d e
f i e s the rf input signal from connector
amplifier V403 consists of two
P401 on the tuning unit and delivers its out-
halves of a dual triode: the cascode
put to crystal mixer CR401.
d r i v e r section, and the grounded
g r i d amplifier section. This stage
erates. a signal which is always 42 mc above
a m p l i f i e s the 42-mc if. frequency
the incoming signal. Its output is also cou-
a n d transformer-couples the out-
pled to crystal mixer CR401.
put to first if. amplifier V404.
C . Crystal Mixer CR401. T h e s i g n a l s
(2) If Amplifier V404. The s i g n a 1
from rf amplifier V401 and from oscillator
f r o m cascode amplifier V403 is
V 4 0 2 are mixed in this stage. Sum and
increased in amplitude and peaked
d i f f e r e n c e frequencies are obtained. The
to 42-mc by first if. amplifier
stage is tuned to the difference frequency
V404.
Figure 27. Tuning unit 3, block diagram.
59
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals