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INTRODUCTION
5.1
The design of the 9057/9059 tv'K:lins/Battery Counters is such that all electronic
components are mounted on printed circuit boards, the assemblies are:-
(a)
Attenuator Assembly 19-0620
)
) Model 9059 only
(b)
560 MHz Amplifier and Pre-scaler 19-0604 )
(c)
Control Assembly 19-0608
(d)
Attenuator Assembly 11-0756
(e)
Amplifier and High Speed Decade Assembly 19-0605
(f)
Readout Assembly 11-0754
(g)
5 MHz Osci I Ia tor Model 9440
(h)
tv'K:lins Power Pack
or
(i)
Battery Power Pack.
ATTENUATOR ASSEMBLY 19-0620 Fig.4.1 (lv\odel 9059 only)
5.2
Input signals in the range 40 MHz to 560 MHz are connected to Channel 'B' input
of Model 9059 only. The slide switch offers direct coupling to the Amplifier and
Pre-scaling Assembly or 20dB attenuation
may
be switched in using conventional means.
AMPLIFIER AND PRE-SCALER ASSEMBLY 19-0604 Fig. 4.3 (lv\odel 9059 only)
5.3
The input signal in the frequency range 40 MHz - 560 MHz is applied to pin 1 of
the p.c.b. Q1 to Q6 form the input amplifier which has a gain of approximately 14.
5.4
Q2 and Q5 are biasing transistors to the bases of Q3 and Q6. C6 and C12, pre-set
capacitors to the emitters of Q1 and Q4 respectively, provide compensation at the
higher frequencies.
5.5
Q7,
QB
and the tunnel diode D1 form the square wave shaping circuit, transistor
Q7 provides a high input impedance to the tunnel diode whilst Q8 ensures a
constant current bias supply. This square wave circuit which determines the sensitivity of the
complete assembly, provides the fast edges to drive Q9, Q10 and IC1 at the lower frequencies.
5-1
9057/9059
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