Akai VS-2EGN - Page 91

© Figs. 7-139 and 7-140 respectively, show the compo-
nents connected into circuit during reception of LOW-
CH and HIGH-CH signals.
a
Vel
s zt
3
8Tel-b oC | FB
PTS 478
a
5 >
2 TD
Fig. 7-140 Circuit configuration
during HIGH-CH reception
Fig. 7-139 Circuit configuration
during LOW-CH reception
@ Both circuits of Figs. 7-139 and 7-140 can be repre-
sented by the equivalent circuit of Fig. 7-141.
Pa
tH. : ehh
PRIMARY SIDE RESPONSE
SECONDARY SIDE RESPONSE
gi
=
=
2, COMBINED RESPONSE
Fig. 7-141 Equivalent circuit of
tuning circuit
FREQUENCY
Fig. 7-142 Frequency response of double tuned circuit
© For the adjustment of this response, mutual induct-
gi= Primary side conductance including output conduct- ance and inductance are adjusted using Ld2 and Lb2 for
ance of RF transistor LOW-CH, and Ld1 and Lb1 for HIGH-CH. The double
go=Secondary side conductance including input con- tuned circuit is better than a single tuned circuit be-
ductance or mixer transistor cause the selectivity is good and flatness in the frequen-
The circuit shown in Fig. 7-141 is a stagger tuned circuit. cy band can be obtained. )
A double tuned circuit consists of primary and secon-
dary resonant circuits with staggered resonant frequen-
cies, which are coupled by mutual inductance. The fre-
quency response is as shown in Fig. 7-142.
Service Manual VS-2EGN
88