GB2344252A - Compact microphone for a portable telephone with a coil for cutting out high-frequency interference - Google Patents
Compact microphone for a portable telephone with a coil for cutting out high-frequency interference Download PDFInfo
- Publication number
- GB2344252A GB2344252A GB9928034A GB9928034A GB2344252A GB 2344252 A GB2344252 A GB 2344252A GB 9928034 A GB9928034 A GB 9928034A GB 9928034 A GB9928034 A GB 9928034A GB 2344252 A GB2344252 A GB 2344252A
- Authority
- GB
- United Kingdom
- Prior art keywords
- microphone
- coil
- portable telephone
- cutting out
- compact
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B15/00—Suppression or limitation of noise or interference
- H04B15/02—Reducing interference from electric apparatus by means located at or near the interfering apparatus
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
- H04B1/54—Circuits using the same frequency for two directions of communication
- H04B1/56—Circuits using the same frequency for two directions of communication with provision for simultaneous communication in two directions
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/08—Microphones
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Telephone Function (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
A coil or coils 20,30 for cutting out high-frequency waves are connected to the output terminals 11,12 of a compact microphone 10 for a mobile phone, and are connected to the telephone main unit 60 by lead lines 40, 50. The output transmission waves from the phone give rise to burst noise, which can cause interference in the microphone. The coils cut out or at least substantially reduce the noise from the high frequency waves letting only speech to be converted to variations in voltage.
Description
COMPACT MICROPHONE FOR A PORTABLE TELEPHONE WITH A COIL
FOR CUTTING OUT HIGH-FREQUENCY WAVES
BACKGROUND OF THE INVENTION 1. Field of the Invention:
The present invention relates to a compact microphone for a portable telephone.
2. Description of the Related Art:
The problem of burst noise occurs when communicating using a portable telephone. Burst noise is noise that can be heard by the conversation partner, and is caused when transmission waves from the portable telephone cover speech blocks inside the portable telephone.
In the prior art, noise was reduced by installing a capacitor having a capacitance matched to the transmission frequency interposed between ground (earth) and portions where speech blocks are vulnerable to being covered by transmission waves. In cases in which transmission waves covered the microphone, ferrite beads were used on the lead lines from the microphone, or the shielding characteristics of the microphone case were strengthened.
However, it is difficulty to determine which portions are vulnerable to being covered by transmission waves for a particular portable telephone terminal. In addition, reinforcement of the shield case conflicts with the trend towards more compact and lightweight microphones.
Further, the addition of ferrite beads and capacitors to counteract noise increases the cost of the portable telephone terminal.
SUMMARY OF THE INVENTION
According to the present invention there is provided a compact microphone for a portable telephone, comprising: a microphone unit; an amplifier for amplifying speech signals detected at the microphone unit; an output terminal; and a coil connected to the output terminal for cutting out or at least substantially reducing high-frequency waves.
The microphone may also have a coil for cutting out high-frequency waves connected to a ground terminal. The coil may be provided inside the microphone unit.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in more detail, by way of example, with reference to the accompanying drawings, in which:
Fig. 1 is a perspective view of a compact microphone for a portable telephone according to one embodiment of the present invention;
Fig. 2 is perspective view with a cutaway portion showing the compact microphone of Fig. 1 incorporated into the main unit of a portable telephone;
Fig. 3 is perspective view of a compact microphone for a portable telephone according to another embodiment of the present invention; and
Fig. 4 is circuit diagram of the compact microphone for a portable telephone according to yet another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to Fig. 1, compact microphone 10 of a portable telephone according to one embodiment of the present invention includes output terminal 11 and ground terminal 12. Output terminal 11 is connected to coil 20 for cutting out high-frequency waves, and can be connected to portable telephone unit 60 by lead line 40. Ground terminal 12 is also connected to coil 30 for cutting out high-frequency waves and can be connected to the ground of the main unit 60 by lead line 50.
Operation of the embodiment shown in Fig. 1 will be explained with reference to Fig. 2.
During communication by portable telephone, transmission waves 90 are outputted from antenna 80 in bursts. Transmission waves 90 cover compact microphone 10 and give rise to burst noise. In the case of a compact microphone of the prior art, the output of the compact microphone is simply connected to portable telephone main unit 60 and burst noise countermeasures are provided on device substrate 70. In the present embodiment, however, the output of the transmission wave cover component, which is the source of burst noise, to device substrate 70 can be prevented or at least substantially reduced by passing the output from the compact microphone 10 through coil 20 for cutting out high-frequency waves, the coil acting as a low-pass filter. In this way, only speech converted to variations in voltage is outputted to device substrate 70, and the need for burst noise countermeasures on device substrate 70 is eliminated.
In cases in which the ground of device substrate 70 is weak, the transmission wave cover component covers device substrate 70 from lead line 50 on the ground side of component microphone 10. This transmission wave cover component can be eliminated by passing it through coil 30 connected to ground terminal 12 of compact microphone 10.
The present invention is not limited to the above-described embodiment, and a configuration is also possible in which, for example, only coil 20 for cutting out high-frequency waves in compact microphone output terminal 11 is employed, and only the lead line 50 is used on the ground side, as shown in Fig. 3.
In this construction, the ground of device substrate 70 to which the compact microphone is connected is made sufficiently strong and can be used when there is no crosstalk transmission wave cover from a weak ground. In this case, the construction of the compact microphone itself is simple because the number of coils is decreased which has the merit of enabling further miniaturization.
The above-described embodiments show countermeasures for cases in which transmission waves cover the microphone itself. However, in cases in which transmission waves cover the lead lines from a compact microphone, a countermeasure against burst noise can be taken by arranging coils 20 and 30 for cutting out high-frequency waves within a compact microphone that includes capacitor microphone 13, amplifier 14 for amplifying speech signals detected at capacitor microphone 13, capacitor 15, output terminal 11, and ground terminal 12 as shown in the circuit diagram of Fig. 4. When transmission waves cover the lead lines themselves, coils 20 and 30 for cutting out high-frequency waves eliminate the transmission wave cover, whereby burst noise is not amplifie by circuits inside the microphone and bust noise can be reduced.
Thus the compact microphones illustrated enable elimination of burst noise without adversely increasing the weight of the portable telephone or increasing costs.
In the compact microphones illustrated, a coil for cutting out high-frequency waves is connected to an output terminal. In addition, a coil for cutting out high-frequency waves may also be connected to the ground terminal. Accordingly, burst noise that is audible to the conversation partner during a conversation using the portable telephone can be essentially eliminated without the need to consider lead-out to analog lines or the addition of circuits for counteracting burst noise to the device substrate on which the compact microphone is installed. The reduction in the number of parts of the portable telephone unit further enables reduced cost and improved mounting efficiency on the device substrate.
While preferred embodiments of the present invention have been described, such description is for illustrative purposes only, and it is to be understood that changes and variations maybe made without departing from the scope of the following claims.
Claims (5)
1. A compact microphone for a portable telephone, comprising:
a microphone unit;
an amplifier for amplifying speech signals detected at the microphone unit;
an output terminal; and
a coil connected to the output terminal for cutting out or at least substantially reducing high-frequency waves.
2. A microphone according to claim 1, including a coil for cutting out high-frequency waves connected to a ground terminal.
3. A microphone according to claim 1 or 2, wherein the coil for cutting out high-frequency waves is provided inside the microphone unit.
4. A compact microphone, substantially as any of the embodiments herein described with reference to the drawings.
5. A portable telephone incorporating a compact microphone in accordance with any of the preceding claims.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33625298A JP2000165982A (en) | 1998-11-26 | 1998-11-26 | Small-sized microphone for portable telephone set |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9928034D0 GB9928034D0 (en) | 2000-01-26 |
| GB2344252A true GB2344252A (en) | 2000-05-31 |
Family
ID=18297213
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9928034A Withdrawn GB2344252A (en) | 1998-11-26 | 1999-11-26 | Compact microphone for a portable telephone with a coil for cutting out high-frequency interference |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2000165982A (en) |
| GB (1) | GB2344252A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4683996B2 (en) * | 2005-05-06 | 2011-05-18 | 株式会社オーディオテクニカ | Condenser microphone |
| JP4919621B2 (en) * | 2005-06-24 | 2012-04-18 | 株式会社オーディオテクニカ | Condenser microphone |
| JP2008005018A (en) * | 2006-06-20 | 2008-01-10 | Namiki Precision Jewel Co Ltd | Multi-functional vibration actuator |
| JP2012239118A (en) * | 2011-05-13 | 2012-12-06 | Panasonic Corp | Portable wireless device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4344184A (en) * | 1980-07-31 | 1982-08-10 | Cetec Corporation | Wireless microphone |
| JPS61262310A (en) * | 1985-05-16 | 1986-11-20 | Kokusai Denshin Denwa Co Ltd <Kdd> | Device for preventing radio wave interference |
| JPH04122111A (en) * | 1990-09-13 | 1992-04-22 | Rion Co Ltd | Preamplifier for capacitor microphone |
| GB2303990A (en) * | 1995-07-31 | 1997-03-05 | Sony Uk Ltd | Microphone amplifier |
| JPH10336794A (en) * | 1997-05-31 | 1998-12-18 | Atsuden Kk | Vibration pickup microphone |
-
1998
- 1998-11-26 JP JP33625298A patent/JP2000165982A/en active Pending
-
1999
- 1999-11-26 GB GB9928034A patent/GB2344252A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4344184A (en) * | 1980-07-31 | 1982-08-10 | Cetec Corporation | Wireless microphone |
| JPS61262310A (en) * | 1985-05-16 | 1986-11-20 | Kokusai Denshin Denwa Co Ltd <Kdd> | Device for preventing radio wave interference |
| JPH04122111A (en) * | 1990-09-13 | 1992-04-22 | Rion Co Ltd | Preamplifier for capacitor microphone |
| GB2303990A (en) * | 1995-07-31 | 1997-03-05 | Sony Uk Ltd | Microphone amplifier |
| JPH10336794A (en) * | 1997-05-31 | 1998-12-18 | Atsuden Kk | Vibration pickup microphone |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000165982A (en) | 2000-06-16 |
| GB9928034D0 (en) | 2000-01-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |