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Oscillation frequency control circuit

A technology for controlling circuits and oscillation frequency, which is applied in the field of oscillation frequency control circuits, and can solve the problem of high oscillator prices

Active Publication Date: 2010-12-08
NIHON DEMPA KOGYO CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, the price of these oscillators is generally higher, so the reference signal from these oscillators is distributed and used as the reference signal source of the device

Method used

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  • Oscillation frequency control circuit
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  • Oscillation frequency control circuit

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0123] "Other Embodiment 1"

[0124] In addition, in the above-mentioned example, the pulse output from the PWM circuit 22 is generated based on the latest control voltage information detected by the level detection circuit 23, but it is also possible to store the default voltage information and use the PWM duty cycle to output pulse generation information.

[0125] Specifically, the memory 21 stores a central voltage value within an appropriate range for the control voltage of the voltage-controlled oscillator 15, and the corresponding PWM duty ratio becomes 50%. Therefore, if the voltage-controlled oscillator 14 If the control voltage operates at 0-3.3V, it is set to a control voltage of 3.3 / 2V. In addition, any voltage value other than the central voltage value may be stored and a corresponding control voltage may be set.

[0126] If the default voltage information is used, the components of the level detection circuit 23 and the AD converter 25, and the voltage / PMW duty ...

Embodiment approach 2

[0135] Furthermore, as another embodiment (another embodiment 2), this circuit has a configuration corresponding to the above-mentioned change over time. refer to Figure 5 This other second embodiment will be described. Figure 5 It is a schematic diagram of the aging change characteristic table.

[0136] In this circuit, the voltage / PMW duty ratio table is stored in the memory 21, but instead of this table, the Figure 5 table of time-varying characteristics.

[0137] [Characteristic table of aging change: Figure 5 ]

[0138] Figure 5 In the relationship between the voltage information and the PWM duty ratio in the time-dependent change characteristic table, a time factor is further set.

[0139] Specifically, appropriate voltage information is set with respect to the elapse of time, and a PWM duty ratio is set corresponding to the voltage information and stored in a table.

[0140] The CPU 20 includes a timer inside, and measures the elapse of time.

[0141] In ot...

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Abstract

An oscillation frequency control circuit for correcting its frequency, keeping the oscillation frequency stable when self-oscillating, and oscillating with a control voltage generated by making a fixed voltage given from outside variable. The oscillation frequency control circuit comprises a voltage-controlled oscillator (15), a divider (16), a phase comparator (12), a loop filter (14), a detecting circuit (17), a PWM circuit (22), a memory (21), a control voltage varying circuit (26), a selection switch (13) for connecting / disconnecting the phase comparator (12) and the loop filter (14) and selecting / outputting a control voltage from the control voltage varying circuit (26), and a CPU (20). The CPU selects / outputs the control voltage preferentially according to the command of the controlvoltage selection. If the command is not given and the level of the outside reference signal detected by the detecting circuit (17) is within an adequate range, it turns the selection switch (13) on.If the command is not given and the level of the outside reference signal is out of the adequate range, it turns the selection switch (13) off and outputs information about pulse generation stored inthe memory (21) to the PWM circuit (22).

Description

technical field [0001] The present invention relates to an oscillation frequency control circuit of an oscillator, in particular to an oscillation frequency control circuit that synchronizes with an output signal, corrects its own frequency, and maintains it stably for a certain period of time even when there is no reference signal with high stability. , and can oscillate with a control voltage that can change a fixed voltage from outside. Background technique [0002] In base stations such as next-generation mobile communications and terrestrial digital broadcasting, the accuracy required for frequency reference signals is gradually increasing. [0003] In systems in the fields of broadcasting and communication, cesium frequency reference oscillators, rubidium frequency reference oscillators, frequency synchronization type reference oscillators using GPS signals, etc. are used as frequency reference signals. [0004] However, these oscillators are generally more expensive,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03L7/093H03L7/095H03L7/10
CPCH03L7/14H03L7/146H03L7/107H03L7/1075
Inventor 大西直树
Owner NIHON DEMPA KOGYO CO LTD