Oscillators – Automatic frequency stabilization using a phase or frequency... – Particular frequency control means
Patent
1997-11-26
1999-08-10
Grimm, Siegfried H.
Oscillators
Automatic frequency stabilization using a phase or frequency...
Particular frequency control means
331177V, 331179, H03B 504, H03L 7099, H03L 718
Patent
active
059364742
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to an electronic device comprising an adjustable element which has characteristic features which are to return to a certain pattern.
The invention also relates to a radio telephone handset and a system for acting on said adjustable element.
Such an invention particularly relates to portable radio devices used in mobile telephones for which the adjustable element is the first local oscillator.
In this type of application, the telephone is to receive over a wide frequency range. It happens that, as a result of the spreading of its components, an oscillator is incapable of covering the ranges imposed by the pattern and that corrections are to be made therein. This type of corrections is made by causing a variation in the capacitance of the capacitor or the self-inductance of the coil forming the oscillator resonant circuit.
On this subject could be consulted the French Patent document FR 2 612 017.
The drawback of all this is that the tuning at the end of the manufacturing process remains a costly operation, because the adjustment of the value of a capacitor or of a self-inductance takes time.
The present invention proposes a device of the type defined in the opening paragraph whose adjustment becomes extremely simple.
OBJECT AND SUMMARY OF THE INVENTION
Therefore, such a device is characterized in that said adjustable element comprises a correction element which can be switched by a fuse.
It is noted that the fact that a fuse can be melted is a simple operation which can be rapidly executed and rendered automatic for a check circuit operated at the end of the manufacturing process.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 shows a first electronic device according to the invention,
FIG. 2 shows a system for melting a fuse according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 is shown an oscillator circuit formed by an inductance coil 1, a first external fixed capacitor 2, and a second fixed capacitor 3 connected in parallel to the first one. An integrated circuit 5 contains the active elements which permit of generating the oscillation whose frequency is determined partly by the value of these components 1 and 2. The frequency of this oscillator may be changed by varying a bias voltage of variable diodes 10 and 11. This voltage is produced by a phase-locked loop. This loop is formed by a variable frequency divider 15 whose input derives part of the oscillation and whose output produces a wave whose frequency is equal to the frequency of the input signal divided by a number CH.sub.-- Nb, and a phase detector 17 of which a first input receives the output signal of the divider 15, and of which a second input receives a reference signal produced by a quartz oscillator 20.
Before delivering the apparatus to the client, it is suitable to check whether the oscillator is capable of functioning in the whole frequency range for which it is designed. In other terms, it is to be capable of oscillating for any number CH.sub.-- Nb.
If this oscillation does not occur, according to the invention a fuse 25 is provided. If the oscillation does not take place for a channel, this fuse 25 is melted.
According to the preferred embodiment, the circuit 5 is a circuit manufactured by Motorola registered MC13110/MC1311. Although this circuit already comprises switchable capacitors C1, C2, C3 . . . in the oscillation circuit, it has been found that these are sometimes insufficient capacitors to ensure the desired frequency coverage. When the invention is implemented with this integrated circuit, it guarantees oscillation for all the desired channels in 99% of the cases. In this preferred embodiment the fuse is a CMS component of size 805, thus a small-sized component.
In FIG. 2 is shown a system for melting the fuse. In this Figure the references which are identical to those of the preceding Fig
REFERENCES:
patent: 4689581 (1987-08-01), Talbot
patent: 4816778 (1989-03-01), Weber
patent: 4868525 (1989-09-01), Dias
Grimm Siegfried H.
Halajian Dicran
U.S. Philips Corporation
LandOfFree
Oscillator having correction element switchable by a fuse does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Oscillator having correction element switchable by a fuse, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Oscillator having correction element switchable by a fuse will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1123866