GB2288711A - A field strength detecting apparatus - Google Patents
A field strength detecting apparatus Download PDFInfo
- Publication number
- GB2288711A GB2288711A GB9502295A GB9502295A GB2288711A GB 2288711 A GB2288711 A GB 2288711A GB 9502295 A GB9502295 A GB 9502295A GB 9502295 A GB9502295 A GB 9502295A GB 2288711 A GB2288711 A GB 2288711A
- Authority
- GB
- United Kingdom
- Prior art keywords
- field strength
- channel
- frequency
- value
- correction
- 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- Withdrawn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
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/309—Measuring or estimating channel quality parameters
- H04B17/318—Received signal strength
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/20—Monitoring; Testing of receivers
- H04B17/21—Monitoring; Testing of receivers for calibration; for correcting measurements
Description
2288711
FIELD STRENGTH DETECTING APPARATUS & METHOD
BACKGROUND OF THE INVENTION (Field of the Invention)
The present invention generally relates to a field strength detecting apparatus for detecting field strength (intensity) of a signal received from a mobile radio signal channel. More specifically, the present invention is directed to afield strength detecting apparatus operable only in a frequency range allocated to mobile communication systems, and capable of correcting frequency deviation contained in a field strength value detected from a mobile radio signal of a mobile radio receiver. (Description of the Related Art)
As the frequency range of the radio waves used in the mobile communications, typically known as the automobile telephone, two frequency bands of, for instance, 800 MHz and 1.5 GHz are allocated. Approximately 300 radio channels are set within the bandwidth of about 20 MHz of the respective frequency ranges. On the other hand, the field strength (intensity) measuring apparatuses capable of measuring the field strength of the radio communication waves are commercially available. These commercially available field strength measuring apparatuses may be operated so as to measure the field strength of the radio signals having the frequency bands used in the mobile communication field.
However, since these field strength measuring apparatuses may have general purposes in use, the uniform precision can be io achieved over the wide frequency range. As a result, these field-strength measuring apparatuses are necessarily made bulky at high cost. Thus, although these measuring apparatuses may be transported by way of automobiles and the like, they are not proper for personal portability.
Generally speaking, since the field strength measuring apparatus designed for the mobile communication maintenance purpose need not measure thefield strength of the radio waves in the channels other then the channels allocated to the mobile communication frequency range, if this measuring apparatus is dedicated only to measure the field strength of the signals allocated to the mobile communication frequency range, then the resultant measuring apparatus can be made from a simpler circuit arrangement, and also made compact, i.e., better portability. In Fig. 1, there is shown one conventional field strength detecting apparatus used only in the mobile communication frequency band with the aboved escribed specific circuit arrangement. in this field strength detecting apparatus, the reception signal 1 in the channel determined based on the channel designation data 8 outputted from the channel designating unit 9 is received by the signal receiving unit 2. The output from the signal receiving unit 2 is supplied as field strength information 3 to the field strength detecting unit 4, and the detection signal derived from the field strength detecting unit 4 is outputted as the field strength detected value 5 for the reception signal 1. In this case, the level of the field strength information 3 corresponds to the field strength io is detected value 5 in a 1-to-1 correspondence. For instance, assuming now that when the level of this field strength information 3 is 1 V, the detected value 5 is 10 dBg, if the level of the field strength information 3 becomes 2 V, then the detected value 5 is 20 dBg.
Since the field strength detected value outputted with respect to the inputted field strength information is continuously converted by the field strength detecting unit of the conventional field strength detecting apparatus with keeping the 1-to-1 correspondence, in case that either the high frequency amplifier, or the high frequency filter (both are not shown), which constitute the signal receiving unit, owns deviation caused by the frequency characteristic, when the field strength information which has been deviated by the signal receiving unit is converted as the detected voltage, this detected voltage is varied in accordance with the frequency deviation of the signal receiving unit. As a result, the field strength detected value owns such deviation. Accordingly, even when a plurality of the actually measured field strength are identical to each other, as shown in Fig. 2, the detected values outputted form the field strength detecting unit 4 own different deviation from each other depending on its frequency used for the channel. Therefore, the correct field strength could not be measured over the available frequency range in the mobile communication field.
To solve the above-described problems, one solution has been proposed in Japanese Laid-open Patent Application No. 64- 32538 (opened in 1989).In this second conventional field
1,0 strength detecting apparatus, a plurality of frequency characteristic correcting elements and also a plurality of bandpass filters are employed at the signal receiving end. Then, both of the frequency-characteristic correcting elements and the bandpass filters are sequentially switched in response to the frequencies of the signals transmitted from the transmission end to obtain the reception results. Based upon the reception results, a selection is made of such an optimum frequency characteristic correcting element for the transmission frequency, so that such deviation caused by the frequency characteristic of the signal receiving unit can be maintained within a preselected allowable value.
However, the above-explained second conventional fieldstrength detecting apparatus owns various drawbacks. For instance, since the frequency characteristic correction should be carried out by sending out the testing signal from the transmission end every time the field strength is measured, and in addition, the frequency characteristic correcting elements should be selected in accordance with the signal reception results, this field strength detecting apparatus requires the complex circuit arrangement, and also a plurality of bandpass filters in accordance with the frequency range to be measured, resulting in a bulky apparatus. This may impede portability of the detecting apparatus. Moreover, the characteristic correction cannot be performed unless the signal receiving unit is combined with the signal transmitting unit.
SUMMARY OF THE INVENTION
The preferred embodiments of the present invention have been made in an attempt to solve the above-explained problems, and therefore, have as an object to provide a portable field strength detecting apparatus capable of correcting frequency characteristics independently of the signal transmissing unit.
In one aspect the invention provides a method of measuring field strength in one of a plurality of radio signal frequency channels of a communication system comprising assigning a 'correction value to each frequency channel to compensate for variations in respective receiving characteristics for said channels in a signal receiving unit, receiving the radio signal in the signal receiving unit, producing a detected field strength value for the received signal and correcting the detected value by applying thereto the correction value appropriate to the frequency channel.
In another aspect the invention provides a field strength detecting apparatus for a multi-channel radio communication system comprising a signal receiving unit for receiving signals in any of a plurality of frequency channels, means for producing a detected field strength value for a received signal in a said channel, and means for correcting the detected field strength value by applying thereto a correction value selected from a number thereof according to the channel in which the signal was received.
More specifically, a field strength detecting apparatus of the present invention is directed to a field strength detecting apparatus for measuring field strength of a frequency band allocated to mobile communication. That is, this field strength detecting apparatus is characterised by comprising:
a channel. designating unit for outputting two sets of same channel information used to designate a channel number corresponding to a frequency of a radio signal to be received, said two sets of same channel information being first channel information and second channel information; a signal receiving unit for inputting therein the first channel information derived from said channel designating unit to receive a radio signal having a frequency corresponding to the channel number designated by said first channel information, thereby outputting a field strength level of said received radio signal; a field strength detecting unit for inputting therein the field strength level of said received radio signal derived from said signal receiving unit to output said field strength level as a field strength detected value; and a correction circuit containing a correction value used to correct a frequency characteristic owned by said signal
6- is receiving unit within the frequency band allocated to said mobile communication, for entering therein the secand channel information outputted from said channel designating unit to select the correction value-corresponding to said second channel information, whereby said field strength detected value derived from said field strength detecting unit is corrected based on said selected correction value.
The above-described correction circuit is further comprised of:
a correction memory for storing the channel nunber corresponding to the frequency of the radio signal within the frequency band allocated to said mobile communication and said correction value corresponding to said channel number; an address designating unit for'designating a read address of said correction memory based upon said second channel information supplied from said channel designating unit; and an adding circuit for adding the correction value read from said correction memory to the field strength detected value outputted from said field strength detecting unit.
In accordance with the field strength detecting apparatus with the abovedescribed circuit arrangement, even when the signal receiving unit owns the frequency characteristic, this frequency characteristic is previously measured and then the correction values corresponding to the respective frequencies are stored in the correction memory in connection with these frequencies. As a result, the frequency characteristic of the field strength detected value which has been received by the signal receiving unit and detected by the field strength detecting unit can be corrected in such a manner that the same frequency as the reception frequency is designated and the correction value correspondiiig to this designated frequency is read out from the correction memory, so that the correct field-strength detected value can be obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be described in further detail with reference to the accompanying drawings, in which:
Fig. 1 is a schematic block diagram for representing an arrangement of the conventional field strength detecting apparatus;
Fig. 2 graphically represents a variation in the field strength value detected by the conventional field strength detecting apparatus of Fig. 1, caused by the frequency characteristic;
Fig. 3 is a schematic block diagram for showing an arrangement of a field strength detecting apparatus according to an embodiment of the present invention;
Fig. 4 represents a relationship between a correction. value and a signal channel based on a prepared frequency characteristic; Fig. 5 is a schematic block diagram for indicating an internal arrangement of the correction circuit employed in the field strength detecting apparatus shown in Fig. 3; and
Fig. 6 graphically shows a variation in the corrected field strength value detected from the field strength detecting apparatus of Fig. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fig. 3 is a schematic block diagram for indica-ting an arrangement of a field strength (intensity) detecting -apparatus according to an embodiment of the present invention. It should be noted that the same reference numerals shown in Fig. 1 will be employed as those for indicating the same or similar circuit units of Fig. 3, and therefore no explanations thereof are made in the specification. The field strength detecting apparatus owns such a similar circuit arrangement that the channel designating unit 9 supplies the channel designating data 8 to the signal receiving unit 2, as compared with that of Fig. 1.- A different circuit arrangement of this detecting apparatus is such that channel information 10 indicating which channel is designated is furnished from this channel designating unit 9 to a correction circuit 6 (will be discussed later). Furthermore, a detected value 5 outputted from the field strength detecting unit 4 is supplied to this correction circuit 6 which corrects the detected value 5 based on the channel information 10 to produce a corrected detection value 7. Then, the frequency characteristic is corrected and this corrected detection value 7 is outputted.
In the field strength detecting apparatus with the abovedescribed arrangement, a reception signal 1 having such a frequency determined by the channel designating data 8 derived from the channel designating unit 9 is received by the signal receiving unit 2. Then, the field strength information 3 outputted form this signal receiving unit 2 is supplied to the field strength detecting unit 4 so as to obtain the field -g- strength detected value 5. It should Le undersood ha hlt detected value 5 owns such a frequency characteristic as shown in Fig. 2 referred in the prior art, and therefore cannot constitute a desirable correct field-strength detected value.
Therefore, this detected value 5 is supplied to the correction circuit 6. The correction circuit 6 corrects this detected value 5 with respect to each of preselected channel ranges based upon the channel information 10 supplied from the channel designating unit 9 by using correction values as io represented in Fig. 4.
It should be understood that this correction value can be determined by that the frequency characteristic owned by the signal receiving unit 2 is previously measured, and based on this measured frequency characteristic, this correction value is defined in connection with the signal channels used in the mobile communication where the field strength should be measured by the field strength detecting apparatus according to the present invention.
On the other hand, as shown in Fig. 5, the correction circuit 6 is arranged by a correction unit 13 and an adder 11.
This correction unit 13 is constructed of an address designating unit 130 and a correction memory 131 for previously storing correction values in correspondence with the channel numbers 11011 to 1,30011, and the address as illustrated in Fig. 4. The correction by this correction circuit 6 is performed as follows: That is, the channel information 10 supplied from"the channel designating unit 9 is supplied to the address designating unit 130 of the correction is unit 6, so that a correcting value 12 corresponding to the channel number is read out and then is supplied to-the adder 11. The adder 11 adds this correcting value 12 to the detected value 5 supplied ffom the field strength detecting unit 4, thereby performing the desired correction.
In accordance with the field strength detecting apparatus with the abovedescribed circuit arrangement, since the above- described correction circuit 6 is employed, such a corrected detection value as shown in Fig. 6 may be produced even when the detected value 5 from the field strength detecting unit 4 contains the frequency deviation, as previously explained in the prior art detecting apparatus with reference to the frequency characteristic curve of Fig. 2. In other words, this corrected detection value reflects a very correct field strength value. In this embodiment, in order to reduce this deviation within + 1[dBI to -1[dBI, the entire frequency range is subdivided into six channel regions, and then the correcting values 12 are properly allocated to these six channel regions (see Fig. 4). As apparent from Fig. 4, a large number of channels are set into one channel region whose frequency characteristic is substantially flat, whereas a small number of channels are set into another channel region whose frequency characteristic deviation is large. As a consequence, a total number of channels which are handled as one channel region may be reduced in order to obtain more precise measurement values, as compared with those of Fig. 4. It should be noted that since the graphic representation of Fig. 6 is more or less exaggerated, the deviation is expressed in large sizes.
As previously explained, since the field strength detecting apparatus according to the present invention is comprised with the memory fok previously storing the correcting values used to correct the detected field strengths and the correcting circuit for adding the data (correcting value) read from this memory to the measurement value so as to perform the deviation correction, the deviation depending on the frequency characteristic is corrected based on the correcting value, so that such a field strength detected value with deviation reduced within a predetermined value can be obtained. Furthermore, since the field strength detecting apparatus is designed to measure the field strength only in the radio signals used in the mobile communication range, this field strength detecting apparatus need not have a flat frequency characteristic over a wide range. As a consequence, this detecting apparatus can be made compact, i.e., can own better portability. In addition, as the correcting values read from the memory are derived based on the reception channel information designated to the signal receiving unit, the deviation corrections can be immediately performed in synchronism with the received signal channel.
Although the present invention has been fully described by way of the preferred embodiments thereof with reference to the accompanying drawings, various changes and modifications will be apparent to whose having skill in this field. Therefore, unless these changes and modifications otherwise depart from the scope of the present invention, they should be -12 1 construed as included therein.
Each feature disclosed in this specification (which term includes the claims) andlor shown in the drawings may be incorporated in the invention independently of other disclosed and/or illustrated features.
The appended abstrad as filed herewith is included in the specification by reference.
Claims (5)
1. A method of measuring field strength in one of a plurality of radio signal frequency channels of a communication system comprising assigning a correction value to each frequency channel to compensate for variations in respective receiving characteristics for said channels in a signal receiving unit, receiving the radio signal in the signal receiving unit, producing a detected field strength value for the received signal and correcting the detected value by applying thereto the correction value appropriat6to the frequency channel.
2. A field strength detecting apparatus for a multi-channel radio communication system comprising a signal receiving unit for receiving signals in any of a plurality of frequency channels, means for producing a detected field strength value for a received signal in a said channel, and means for correcting the detected field strength value by applying thereto a correction value selected from a number thereof according to the channel in which the signal was received.
1 2 a 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 3. A field strength detecting apparatus for-measuring field strength of a frequency band allocated to a mobile 3 communication, comprising."
a channel designating unit for outputting two sets of same channel information used to designate a channel number corresponding to a frequency of a radio signal to be received, said two sets of same channel information being first channel information and second channel information; a signal receiving unit for inputting therein the first channel information derived from said channel designating unit to receive a radio signal having a frequency corresponding to the channel number designated by said first channel information, thereby outputting a field strength level of said received radio signal; a field strength detecting unit for inputting therein the field strength level of said received radio signal derived from said signal receiving unit to output said field strength level as a field strength detected value; and a correction circuit containing a correction value used to correct a frequency characteristic owned by said signal receiving unit within the frequency band allocated to said mobile communication, for entering therein the second channel information outputted from said channel designating unit to select the correction value corresponding to said second channel information, whereby said field strength detected value derived from said field strength detecting unit is corrected based on said selected correction value.
1 6 7 8 9 10 11 12 13 14 4. A field strength detecting apparatus as claimed in claim 1 wherein:
3 said correction circuit is further comprised of:
4 a correction memory for storing the channel number corresponding to the frequency of the radio signal within the frequency band allocated to said mobile communication and said correction value corresponding to said channel number; an address designating unit for designating a read address of said correction memory based upon said second channel information supplied from said channel designating unit; and an adding circuit for adding the correction value read from said correction memory to the field strength detected value outputted from said field strength detecting unit.
5. A field strength detecting method or apparatus substantially as herein described with reference to Figures 3 to 6 of the accompanying drawings.
j
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6034279A JPH07221697A (en) | 1994-02-08 | 1994-02-08 | Electric field intensity detector for mobile communication frequency band |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9502295D0 GB9502295D0 (en) | 1995-03-29 |
| GB2288711A true GB2288711A (en) | 1995-10-25 |
Family
ID=12409729
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9502295A Withdrawn GB2288711A (en) | 1994-02-08 | 1995-02-06 | A field strength detecting apparatus |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPH07221697A (en) |
| CN (1) | CN1046069C (en) |
| GB (1) | GB2288711A (en) |
| SG (1) | SG77552A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007114743A1 (en) * | 2006-03-31 | 2007-10-11 | St. Jude Medical Ab | Received signal strength measurement compensation |
| WO2014197122A1 (en) * | 2013-06-04 | 2014-12-11 | Apple Inc. | Methods for calibrating receive signal strength data in wireless electronic devices |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1986000769A1 (en) * | 1984-07-02 | 1986-01-30 | Motorola, Inc. | Self-calibrating signal strength detector |
| EP0500362A2 (en) * | 1991-02-20 | 1992-08-26 | Nec Corporation | Radio receiver capable of correcting the field strength measurement of a radio signal |
| US5239684A (en) * | 1989-07-18 | 1993-08-24 | Kabushiki Kaisha Toshiba | Radio communication apparatus having a function for displaying reception field strength and method of controlling the apparatus |
| EP0601987A2 (en) * | 1992-12-11 | 1994-06-15 | Telefonaktiebolaget Lm Ericsson | Method and apparatus for correcting a received signal strength indication in a radio receiver |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2604578B2 (en) * | 1986-07-14 | 1997-04-30 | 日本電信電話株式会社 | Wireless relay device |
| JP2636308B2 (en) * | 1988-03-08 | 1997-07-30 | 松下電器産業株式会社 | Wireless communication equipment |
| JP2740025B2 (en) * | 1989-11-22 | 1998-04-15 | 株式会社東芝 | Wireless communication device |
| JPH04207326A (en) * | 1990-11-30 | 1992-07-29 | Hitachi Ltd | Radiotelephony set |
| JP3232620B2 (en) * | 1992-02-10 | 2001-11-26 | 松下電器産業株式会社 | Wireless telephone |
-
1994
- 1994-02-08 JP JP6034279A patent/JPH07221697A/en active Pending
-
1995
- 1995-02-06 SG SG1996005296A patent/SG77552A1/en unknown
- 1995-02-06 GB GB9502295A patent/GB2288711A/en not_active Withdrawn
- 1995-02-08 CN CN95102792A patent/CN1046069C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1986000769A1 (en) * | 1984-07-02 | 1986-01-30 | Motorola, Inc. | Self-calibrating signal strength detector |
| US5239684A (en) * | 1989-07-18 | 1993-08-24 | Kabushiki Kaisha Toshiba | Radio communication apparatus having a function for displaying reception field strength and method of controlling the apparatus |
| EP0500362A2 (en) * | 1991-02-20 | 1992-08-26 | Nec Corporation | Radio receiver capable of correcting the field strength measurement of a radio signal |
| EP0601987A2 (en) * | 1992-12-11 | 1994-06-15 | Telefonaktiebolaget Lm Ericsson | Method and apparatus for correcting a received signal strength indication in a radio receiver |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007114743A1 (en) * | 2006-03-31 | 2007-10-11 | St. Jude Medical Ab | Received signal strength measurement compensation |
| WO2014197122A1 (en) * | 2013-06-04 | 2014-12-11 | Apple Inc. | Methods for calibrating receive signal strength data in wireless electronic devices |
| US9401769B2 (en) | 2013-06-04 | 2016-07-26 | Apple Inc. | Methods for calibrating receive signal strength data in wireless electronic devices |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07221697A (en) | 1995-08-18 |
| SG77552A1 (en) | 2001-01-16 |
| GB9502295D0 (en) | 1995-03-29 |
| CN1046069C (en) | 1999-10-27 |
| CN1115140A (en) | 1996-01-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2003511897A (en) | Calibration of mobile devices using the folding module | |
| US4605902A (en) | Hybrid junction signal combiner | |
| KR20010113973A (en) | Improved reverse path autogain control | |
| JPH07297749A (en) | Radio equipment provided with plural antennas | |
| CN1085365A (en) | A kind of communication system | |
| CA2373516A1 (en) | Method and apparatus for obtaining optimal performance in a receiver | |
| KR20000006306A (en) | Telecommunicator Testing Apparatus and Method of Operation Therefor | |
| AU654166B2 (en) | Radio transceiver system | |
| EP0583306B1 (en) | Device and method for adjusting a bandpass filter, especially a combiner filter | |
| EP0089649A2 (en) | Radio transmitter/receiver | |
| GB2288711A (en) | A field strength detecting apparatus | |
| EP0601743A1 (en) | Tuning of a radio receiver | |
| US6049562A (en) | Multi-branch frequency-hopping receiver | |
| US6393258B1 (en) | Process and system for adjusting the level of the spurious lines of the output frequency spectrum of a single-sideband frequency transposition device, in particular incorporated into a mobile telephone | |
| EP0665662B1 (en) | Reception field detection apparatus | |
| JPH06334630A (en) | Spread spectrum communication method | |
| JP2000295120A (en) | Interference wave level detection circuit, narrow band interference wave limiting device using the same and communication equipment using the same | |
| FI80817C (en) | Device for checking the condition of the base station antenna in cellular telephone systems | |
| WO2001056191A1 (en) | Method and arrangement for controlling transmitted power in a multi-carrier system | |
| JPS61121537A (en) | Electric power control circuit | |
| JP3606903B2 (en) | Volume level adjustment device | |
| KR19990042237A (en) | Base station receiver in mobile communication system using variable band pass filter | |
| SU809005A1 (en) | Device for measuring non-square law characteristics of uhf detectors | |
| EP0142586A1 (en) | A filter arrangement with active elements | |
| EP1157463A1 (en) | Tuning arrangement |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |