CSTCW24M0X53-R0 Datasheet, PDF (11/32 Pages) Murata Manufacturing Co., Ltd. – Ceramic Resonator

P17E.pdf
2012.10.31 ^{Note • Please read rating and CAUTION (for storage, operating, rating, soldering, mounting and handling) in this catalog to prevent smoking and/or burning, etc.}
• This catalog has only typical specifications because there is no space for detailed specifications. Therefore, please review our product specifications or consult the approval sheet for product specifications before ordering.
Principles of CERALOCK^{® 2}
2. Basic Oscillation Circuits
Generally, basic oscillation circuits can be grouped into
the following 3 categories.
ᶃ Use of positive feedback
ᶄ Use of negative resistance element
ᶅ Use of delay in transfer time or phase
In the case of ceramic resonators, quartz crystal
oscillators, and LC oscillators, positive feedback is the
circuit of choice.
Among the positive feedback oscillation circuit using an
LC, the tuning type anti-coupling oscillation circuit,
Colpitts and Hartley circuits are typically used.
See Fig. 2-6.
In Fig. 2-6, a transistor, which is the most basic
amplifier, is used.
The oscillation frequencies are approximately the same
as the resonance frequency of the circuit consisting of L,
CL1 and CL2 in the Colpitts circuit or consisting of L1
and L2 in the Hartley circuit. These frequencies can be
represented by the following formulas. (Refer to Note 3
on page 11.)
(Colpitts Circuit)
fosc. =
1
CL1 · CL2
CL1 + CL2
(2-4)
(Hartley Circuit)
fosc. =
1
(2-5)
In an LC network, the inductor is replaced by a ceramic
resonator, taking advantage of the fact that the
resonator becomes inductive between resonant and anti-
resonant frequencies.
This is most commonly used in the Colpitts circuit.
The operating principle of these oscillation circuits can
be seen in Fig. 2-7. Oscillation occurs when the
following conditions are satisfied.
Loop Gain G = αɾβ ʾ 1
Phase Amount
θ = θ 1 + θ 2 = 360°×n (n = 1, 2,ʜ)
(2-6)
In Colpitts circuit, an inverter of θ 1 = 180° is used, and
it is inverted more than θ 2 = 180° with L and C in the
feedback circuit. The operation with a ceramic resonator
can be considered the same.
CL1
CL2
L1
L2
2
L
C
Colpitts Circuit
Hartley Circuit
Fig. 2-6 Basic Configuration of LC Oscillation Circuit
Amplifier
1
Feedback Circuit
Feedback Ratio :
Phase Shift : 2
Oscillation Conditions
Loop Gain G=Ћ·Ќ ʾ 1
Phase Shift В = В1+ В2=360°×n
Fig. 2-7 Principle of Oscillation
9