CA2003831A1 - Radio communication apparatus - Google Patents
Radio communication apparatusInfo
- Publication number
- CA2003831A1 CA2003831A1 CA002003831A CA2003831A CA2003831A1 CA 2003831 A1 CA2003831 A1 CA 2003831A1 CA 002003831 A CA002003831 A CA 002003831A CA 2003831 A CA2003831 A CA 2003831A CA 2003831 A1 CA2003831 A1 CA 2003831A1
- Authority
- CA
- Canada
- Prior art keywords
- amplifier
- frequency signal
- transmission
- buffer
- voltage
- 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.)
- Abandoned
Links
Landscapes
- Transmitters (AREA)
- Transceivers (AREA)
Abstract
ABSTRACT
The invention provides a radio communication apparatus, which includes means for preventing unwanted and unnecessary radiation at the start of a radio transmission. The apparatus of the present invention has a simple delay circuit for slowly increasing the voltage applied to an amplifier in a transmission unit including an oscillator, which generates a high-frequency signal of a desired carrier, a buffer, and the amplifier to which is input the high-frequency signal from the oscillator via the buffer and which amplifies the signal and transmits data via an antenna. The delay circuit is connected to a voltage line applied to the amplifier and slowly increases the voltage at the start of the radio wave transmission. The input impedance of the amplifier is prevented from sharply changing and is only allowed to change slowly. The change of the input impedance of the amplifier is translated into a change of load impedance of the oscillator, the amount of such impedance change being decreased by the operation of the buffer. Thus, it is possible to prevent the generation of unnecessary radiation at the start of the radio wave transmission.
The invention provides a radio communication apparatus, which includes means for preventing unwanted and unnecessary radiation at the start of a radio transmission. The apparatus of the present invention has a simple delay circuit for slowly increasing the voltage applied to an amplifier in a transmission unit including an oscillator, which generates a high-frequency signal of a desired carrier, a buffer, and the amplifier to which is input the high-frequency signal from the oscillator via the buffer and which amplifies the signal and transmits data via an antenna. The delay circuit is connected to a voltage line applied to the amplifier and slowly increases the voltage at the start of the radio wave transmission. The input impedance of the amplifier is prevented from sharply changing and is only allowed to change slowly. The change of the input impedance of the amplifier is translated into a change of load impedance of the oscillator, the amount of such impedance change being decreased by the operation of the buffer. Thus, it is possible to prevent the generation of unnecessary radiation at the start of the radio wave transmission.
Description
. ~003831.
Rl~DIO COMHUNICATION APPARAllJS
The present invention relates to a radio communication apparatus capable of keeping one radio transmitter from interfering with another when a plurality of adjoining radio transmitters are simultaneously transmitting radio waves.
In a radio communication system having a plurality of radio communication apparatuses capable of simultaneous communication, the unwanted xadiation generated by one radio communication apparatus at the start of radio transmission interferes with data transmission of other apparatuses while the plurality of adjoining radio communication apparatuses are carrying on communication simultaneously.
A radio communication apparatus generally comprises an oscillator for generating a high-frequency signal of a carr~er wfive and an amplifier to --~
lS amplify the high-frequency signal. Conventionally, a buffer is placed between the oscillator and the amplifier to reduce imped~nce changes seen from the oscillator in order that changes in the input impedance of the amplifier may not be translated directly into changes of load on the oscillator when the power ~upply of the amplifier is switched from OFF to ON
or from ON to OFF.
The buffer i8 generally composed of an isolator, an attenuator, a buffer amplifier or a combination of these.
However, the prior art has various disadvan~ages, including the fact that ~he buffer circuit itself is bulky because the buffering capability required for the buffer i8 high and this detracts from any attempts to make the radio~transmitter compact and to reduce manufacturing cost.
If an isolator having high buffering capability i8 used, for instance, the buffer i~ not suitable for general purpose use because its usable frequency band is extremely narrow and is a relatively eYpensive product 30 because it isldifficultl,to luse it lin common with other models as a means of -reducing co~t. As for an attenuator, on the other hand, its buffering ~ -capability~improves~as the amount of attenuation is increased. However, increased amplification is required to make up ~or the attenuation of the attenuator, in order to obtain the same transmission power, which mitigates .
against reduction in power consumption.
PAT 15176~
An object of the present invention i9 to provide a radio communication apparatus, which includes means for preventing unwanted snd unneceissary radiation at the start of a radio transmission.
Another object of the present invention is to provide a relatively small and low-priced radio communication apparatus by utilizing a simple circuit to prevent such spurious radiation.
To realize the above objects, the radio communication apparatus of the present invention has a simple delay circuit for slowly increasing the voltage applied to an ampllfisr in a transmission unit including an oscillator, which generates a high-frequency signal of a desired carrier, a buffer, and the amplifier to which is input the high-frequency signal from the oscillator via the buffer and which amplifies the signal and transmits data via an antenna.
The delay circuit is connected to a voltage line applied to the amplifier and slowly increases the voltage at the start of the radio wave transmission. The input impedance of the amplifier is prevented from sharply changing but is only allowed to change slowly. The change of the input impedance of the amplifier is translated into a change of load impedance of the oscillator, the amount of such impedance change being 20 decreased by the operation of the buffer. Thus, it is possible to prevent ~-~; ~the generation of unnecessary radiation at the start of the radio wave transmission.
It may be noted that the delay time ~T should be 1 .TN (TN - 2-~or more, when the oscillator consists of a frequency synthesizer using ~ L
circuits and has a natural frequency of WN.
The invention vill now be described further by way of eYample only and ~;
with reference to the accompanying drawings, wherein:
Fig. 1 is a block diagram illustrating transmission and control units of a radio communication apparatus embodying the present invention;
30 ~ i Fig. 2 is~a circuit diagram illustrating a first example of a transmission power supply circuit with delay, embodying the present invention; and Fig. 3 i8 a circuit diagram illustrating a second eYample of a transmission power supply circuit with delay, embodying the present - 35 invention.
~:- : , 20038~1 Referring to the accompanying drawings, and particularly to Fig. 1, a transmission unit 1 has an oscillator 2, a buffer 3, a transmission output stags amplifier 4, and a transmission power supply circuit 10 having built-in delay. An output of the oscillator 2 is inputted to the transmission output stage amplifier 4 via the buffer 3. The output of the transmission output stage amplifier 4 i9 connected to an antenna S.
A control unit 6 sends out a frequency specifying signal 7 and a data signal 8 to the osclllator 2, and a transmission power supply control signal 9 to the transmission power supply circuit 10.
In operation, the control un~t 6 sends out the frequency specif~ing signal 7 to determine the oscillation frequency of the oscillator 2 when the radio communication apparatus starts transmission. The oscillator 2 thereby oscillates to provide a high frequency signal of a desired carrier frequency at a predetermined time later. The control unit 6 subsequently sends out the transmission power supply control signal 9 to the transmission power supply circuit 10 with the predetermined passage of time needed to stabilize the oscillation frequency of the oscillator 2 and applies the power supply voltage to the transmission output stage amplifier 4. At this time, the power supply voltage applied to the transmission output stage amplifier 4 is prevented from sharply rising but allowed to rise slowly because of the delaying operation of the transmission power supply circuit 10. In this way, as the power supply voltage applied to the transmission output stage `~ ampllfier 4 ~lowly changes from OFF to ON, the input impedance of the transmission output stage amplifier 4 is also prevented from sharply ;~
changing but is allowed to change slowly. The change of the input impedance of~the transmission output stage amplifier 4 is translated into a change of load impedance of the oscillator 2 while the amount of the impedance change is reduced by the operation of the buffer 3. With this arrangement, the buffer 3 makes it possible to prevent the generation of unnecessary ~ 30 radiation at the start!,of radio waye transmission without using - sophisticated devices or circuits.
Referring still to the drawings, the transmission power supply circuit - embodying the present invention will now be described.
,rF,~
~ PAT 151~6~
~-` 2003831 In Fig. 2, an IC 21 is a stabilized power supply IC having a voltage comparison input terminal. Input voltage 24 i8 applied to IC 21 when a switch 22 is in it6 stationary closed state and the output of the IC 21 is divided by voltage dividing resistors R2, R3 and received by a voltage comparison input terminal of the IC 21 for comparison with a reference voltage, so that a stabilized output voltage 25 is obtained.
Assume a transmission power supply control signal 23 i9 suddenly applied, which closes the switch 22. Voltage appears at the output terminal of the IC 21 because input voltage 24 is now applied to the IC 21. However, the instantaneous operation of series-connected resistor Rl and capacitor C
(see Fig. 2) causes the voltage dividing resistor R2 to be bypassed and the voltage divided by the resistor Rl and the voltage dividing resistors R2, R3 is applied to the voltage comparison input terminal of the IC 21.
Consequently, the IC 21 is controlled so that the rate of increase in output voltage is reduced. As a result, the net effect upon the output voltage 25 is that it rises slowly instead of sharply.
Fig. 3 shows an IC 31 which is a 3-terminal regulator and is used as a constant-voltage power supply. ~hen a transmission power supply control signal 33 i8 applied to close switch 32, input voltage 34 is applied to the 20 IC 31 and output voltage 35 is integratet by the output impedance of the IC ~ -31 and the capacitance of a capacitor Cl, to provide slow rising characteristics.
As set forth above, the radio communication apparatus according to the present invéntion has the transmission power supply circuit designed with a 25~ built-in delay to make the pover supplied to the transmission output stage ~ -amplifier have slow rising characteristics, whereby it is possible to prevent~the generation of the unwanted radiation at the start of radio wave transmission~and to free other transmitte~s from interference.
AI 15176~
Rl~DIO COMHUNICATION APPARAllJS
The present invention relates to a radio communication apparatus capable of keeping one radio transmitter from interfering with another when a plurality of adjoining radio transmitters are simultaneously transmitting radio waves.
In a radio communication system having a plurality of radio communication apparatuses capable of simultaneous communication, the unwanted xadiation generated by one radio communication apparatus at the start of radio transmission interferes with data transmission of other apparatuses while the plurality of adjoining radio communication apparatuses are carrying on communication simultaneously.
A radio communication apparatus generally comprises an oscillator for generating a high-frequency signal of a carr~er wfive and an amplifier to --~
lS amplify the high-frequency signal. Conventionally, a buffer is placed between the oscillator and the amplifier to reduce imped~nce changes seen from the oscillator in order that changes in the input impedance of the amplifier may not be translated directly into changes of load on the oscillator when the power ~upply of the amplifier is switched from OFF to ON
or from ON to OFF.
The buffer i8 generally composed of an isolator, an attenuator, a buffer amplifier or a combination of these.
However, the prior art has various disadvan~ages, including the fact that ~he buffer circuit itself is bulky because the buffering capability required for the buffer i8 high and this detracts from any attempts to make the radio~transmitter compact and to reduce manufacturing cost.
If an isolator having high buffering capability i8 used, for instance, the buffer i~ not suitable for general purpose use because its usable frequency band is extremely narrow and is a relatively eYpensive product 30 because it isldifficultl,to luse it lin common with other models as a means of -reducing co~t. As for an attenuator, on the other hand, its buffering ~ -capability~improves~as the amount of attenuation is increased. However, increased amplification is required to make up ~or the attenuation of the attenuator, in order to obtain the same transmission power, which mitigates .
against reduction in power consumption.
PAT 15176~
An object of the present invention i9 to provide a radio communication apparatus, which includes means for preventing unwanted snd unneceissary radiation at the start of a radio transmission.
Another object of the present invention is to provide a relatively small and low-priced radio communication apparatus by utilizing a simple circuit to prevent such spurious radiation.
To realize the above objects, the radio communication apparatus of the present invention has a simple delay circuit for slowly increasing the voltage applied to an ampllfisr in a transmission unit including an oscillator, which generates a high-frequency signal of a desired carrier, a buffer, and the amplifier to which is input the high-frequency signal from the oscillator via the buffer and which amplifies the signal and transmits data via an antenna.
The delay circuit is connected to a voltage line applied to the amplifier and slowly increases the voltage at the start of the radio wave transmission. The input impedance of the amplifier is prevented from sharply changing but is only allowed to change slowly. The change of the input impedance of the amplifier is translated into a change of load impedance of the oscillator, the amount of such impedance change being 20 decreased by the operation of the buffer. Thus, it is possible to prevent ~-~; ~the generation of unnecessary radiation at the start of the radio wave transmission.
It may be noted that the delay time ~T should be 1 .TN (TN - 2-~or more, when the oscillator consists of a frequency synthesizer using ~ L
circuits and has a natural frequency of WN.
The invention vill now be described further by way of eYample only and ~;
with reference to the accompanying drawings, wherein:
Fig. 1 is a block diagram illustrating transmission and control units of a radio communication apparatus embodying the present invention;
30 ~ i Fig. 2 is~a circuit diagram illustrating a first example of a transmission power supply circuit with delay, embodying the present invention; and Fig. 3 i8 a circuit diagram illustrating a second eYample of a transmission power supply circuit with delay, embodying the present - 35 invention.
~:- : , 20038~1 Referring to the accompanying drawings, and particularly to Fig. 1, a transmission unit 1 has an oscillator 2, a buffer 3, a transmission output stags amplifier 4, and a transmission power supply circuit 10 having built-in delay. An output of the oscillator 2 is inputted to the transmission output stage amplifier 4 via the buffer 3. The output of the transmission output stage amplifier 4 i9 connected to an antenna S.
A control unit 6 sends out a frequency specifying signal 7 and a data signal 8 to the osclllator 2, and a transmission power supply control signal 9 to the transmission power supply circuit 10.
In operation, the control un~t 6 sends out the frequency specif~ing signal 7 to determine the oscillation frequency of the oscillator 2 when the radio communication apparatus starts transmission. The oscillator 2 thereby oscillates to provide a high frequency signal of a desired carrier frequency at a predetermined time later. The control unit 6 subsequently sends out the transmission power supply control signal 9 to the transmission power supply circuit 10 with the predetermined passage of time needed to stabilize the oscillation frequency of the oscillator 2 and applies the power supply voltage to the transmission output stage amplifier 4. At this time, the power supply voltage applied to the transmission output stage amplifier 4 is prevented from sharply rising but allowed to rise slowly because of the delaying operation of the transmission power supply circuit 10. In this way, as the power supply voltage applied to the transmission output stage `~ ampllfier 4 ~lowly changes from OFF to ON, the input impedance of the transmission output stage amplifier 4 is also prevented from sharply ;~
changing but is allowed to change slowly. The change of the input impedance of~the transmission output stage amplifier 4 is translated into a change of load impedance of the oscillator 2 while the amount of the impedance change is reduced by the operation of the buffer 3. With this arrangement, the buffer 3 makes it possible to prevent the generation of unnecessary ~ 30 radiation at the start!,of radio waye transmission without using - sophisticated devices or circuits.
Referring still to the drawings, the transmission power supply circuit - embodying the present invention will now be described.
,rF,~
~ PAT 151~6~
~-` 2003831 In Fig. 2, an IC 21 is a stabilized power supply IC having a voltage comparison input terminal. Input voltage 24 i8 applied to IC 21 when a switch 22 is in it6 stationary closed state and the output of the IC 21 is divided by voltage dividing resistors R2, R3 and received by a voltage comparison input terminal of the IC 21 for comparison with a reference voltage, so that a stabilized output voltage 25 is obtained.
Assume a transmission power supply control signal 23 i9 suddenly applied, which closes the switch 22. Voltage appears at the output terminal of the IC 21 because input voltage 24 is now applied to the IC 21. However, the instantaneous operation of series-connected resistor Rl and capacitor C
(see Fig. 2) causes the voltage dividing resistor R2 to be bypassed and the voltage divided by the resistor Rl and the voltage dividing resistors R2, R3 is applied to the voltage comparison input terminal of the IC 21.
Consequently, the IC 21 is controlled so that the rate of increase in output voltage is reduced. As a result, the net effect upon the output voltage 25 is that it rises slowly instead of sharply.
Fig. 3 shows an IC 31 which is a 3-terminal regulator and is used as a constant-voltage power supply. ~hen a transmission power supply control signal 33 i8 applied to close switch 32, input voltage 34 is applied to the 20 IC 31 and output voltage 35 is integratet by the output impedance of the IC ~ -31 and the capacitance of a capacitor Cl, to provide slow rising characteristics.
As set forth above, the radio communication apparatus according to the present invéntion has the transmission power supply circuit designed with a 25~ built-in delay to make the pover supplied to the transmission output stage ~ -amplifier have slow rising characteristics, whereby it is possible to prevent~the generation of the unwanted radiation at the start of radio wave transmission~and to free other transmitte~s from interference.
AI 15176~
Claims
IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A radio communication apparatus comprising:
a transmission unit having oscillation means for generating a high-frequency signal of a desired carrier wave, amplifier means for amplifying said high-frequency signal, buffer means for preventing said high-frequency signal from fluctuating due to changes of load of said amplifier means, and delay means for constraining a voltage applied to said amplifier means at the start of radio transmission to a rate of rise in which such voltage change does not cause said high-frequency signal of said oscillation means to fluctuate; and control means for commanding said oscillation means so as to generate said high-frequency signal of said desired carrier wave and for commanding said delay means to operate after stabilization of said high-frequency signal.
a transmission unit having oscillation means for generating a high-frequency signal of a desired carrier wave, amplifier means for amplifying said high-frequency signal, buffer means for preventing said high-frequency signal from fluctuating due to changes of load of said amplifier means, and delay means for constraining a voltage applied to said amplifier means at the start of radio transmission to a rate of rise in which such voltage change does not cause said high-frequency signal of said oscillation means to fluctuate; and control means for commanding said oscillation means so as to generate said high-frequency signal of said desired carrier wave and for commanding said delay means to operate after stabilization of said high-frequency signal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63-301735 | 1988-11-28 | ||
| JP63301735A JPH02146822A (en) | 1988-11-28 | 1988-11-28 | Radio communication equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2003831A1 true CA2003831A1 (en) | 1990-05-28 |
Family
ID=17900532
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002003831A Abandoned CA2003831A1 (en) | 1988-11-28 | 1989-11-24 | Radio communication apparatus |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH02146822A (en) |
| CA (1) | CA2003831A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102004031603B4 (en) * | 2004-06-30 | 2008-04-17 | Eads Deutschland Gmbh | Method for shaping signal spectra and circuit for carrying out the method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS50113111A (en) * | 1974-02-14 | 1975-09-05 | ||
| JPS58213537A (en) * | 1982-06-04 | 1983-12-12 | Alps Electric Co Ltd | Multichannel accessing device in simple radio communication system |
| JPS5999851A (en) * | 1982-11-29 | 1984-06-08 | Nec Corp | Signal control circuit |
-
1988
- 1988-11-28 JP JP63301735A patent/JPH02146822A/en active Pending
-
1989
- 1989-11-24 CA CA002003831A patent/CA2003831A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02146822A (en) | 1990-06-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3247452B2 (en) | How to switch on the transmitter in a dual mode mobile phone | |
| US4367443A (en) | Radio frequency signal power amplifier | |
| US6456225B1 (en) | Reflector circuit | |
| WO2004021558A3 (en) | Method of modulation gain calibration and system thereof | |
| CA2135816C (en) | Transmission circuit with improved gain control loop | |
| GB2318003A (en) | Automatic gain control in direct sequence spread spectrum communication receiver | |
| KR920001866A (en) | Sensitivity switching circuit for radio | |
| US6734745B2 (en) | Oscillator and communication apparatus using the same | |
| JPS6349935B2 (en) | ||
| CA2003831A1 (en) | Radio communication apparatus | |
| US5223801A (en) | Crystal oscillator and transmitter operating at the third harmonic of the fifth overtone of a crystal | |
| US5994964A (en) | Gain-control-type transistor power amplifier | |
| US7259629B2 (en) | Variable gain amplifier with improved control characteristics linearity | |
| US3875517A (en) | Tracking phase detector for surface wave correlators | |
| US5394120A (en) | Device for testing an amplifier | |
| KR940000927B1 (en) | Power amp circuit | |
| KR850000158A (en) | Squelch Circuit | |
| US2930003A (en) | Transistorized harmonic generator | |
| KR930017358A (en) | Two Handset Cordless Phone Systems with Base Unit Using Voltage Control Modified Oscillator (VCXO) | |
| US3584302A (en) | Encoder-decoder circuit including a continuously operable oscillator circuit | |
| KR910021016A (en) | Circuit device with electrically controllable transmission characteristics | |
| KR0154732B1 (en) | Circuit for protecting receiving part from spurious noise in digital radio transceiver | |
| KR100499746B1 (en) | Radio Frequency communication module | |
| KR840000116A (en) | Radio transmitter modulation control circuit | |
| GB1039830A (en) | A radio-frequency transistorised amplifier |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |