JPS58210729A - Double communication method and device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to duplex communication systems and, more particularly, to methods for implementing duplex communication within a single frequency band of radio frequencies.

A duplex communication system is defined as a communication system in which two functions, transmitting and receiving, can be performed simultaneously. The main known systems include wireless telephones and cordless telephones.

There are two basic types of wireless telephone systems: Mobile Telephone Service (MTS) and Improved Mobile Telephone System (IMTS). In each system, the wireless channel to be used for communication must be selected before commencing the communication. At MTS, users:
Wireless channels must be manually switched until a free (currently unused) channel is found.

IMTS has an automatic scanning system that automatically searches for available radio channels until a free channel is found and then locked onto it. however,
In both systems, in order to provide two-way communication, the transmitting and receiving frequencies are usually divided into fixed frequency bands, so there is still the inconvenience of having to operate in a button-to-talk mode. . The user must press the microphone switch to transmit and release it to receive. This mode of operation is a hassle because each party usually has to say "over" or some other sign when they are ready to listen to the other party. Yes. Because the nature of this system is that the person speaking is not listening to what the other person is saying when he or she is speaking, such communications do not allow one person to interrupt the other person.

Wireless telephones are stand-alone systems, whereas cordless telephones, in contrast, are devices that simply add on to existing conventional topline telephone systems. That is, wireless communications are used to transmit the voice signals of the caller from the parent device to the remote device, and further to transmit the voice signals from the operator of the remote device to the parent station and then to the central telephone system. . Thus, telephone conversations may occur that are indistinguishable from similar conversations that occur on conventional wireline systems. Therefore, audio transmission and reception occur simultaneously.

This is in contrast to radiotelephones or transceivers, which do not transmit and receive simultaneously.

The use of cordless telephones ranges widely from answer-only cordless fist handsets to cordless devices 1 that perform all the functions of a wired telephone device. A true cordless telephone is one that operates in conjunction with a parent station connected to a standard telephone line. The maximum operating range is approximately 50 feet (approximately 15 meters) to 500 feet (approximately 15 meters).
152 meters) or more. Most of them work on the same general principle, with both the parent and remote handsets each containing both a transmitter and a receiver, where the parent transmits a signal to a receiver built into the remote handset. It connects telephone lines to The operator of the remote handset then transmits back to the receiver of the parent device, where this received voice information is sent to the telephone line.

Cordless telephone systems typically have two devices, a parent device or station connected directly to the telephone line through a connector, and a wireless remote device. In current models, the parent device transmits voice information at a low frequency of about 1.7 MHz from the telephone line to which it is directly attached. The parent device also has approximately 49.5 MHz in the radio spectrum.
It also has a built-in receiver that operates at 8MHz. The parent device is
It is equipped with an antenna that is used to receive transmissions from mobile devices on this radio frequency. The parent device must be connected directly to the AC line within the building to obtain operating current. However, the wiring within the building in which the parent device is installed has another very heavy use for the parent device. The output of the 1.7 MHz parent transmitter system is:
It is generally separated into each side of the AC line through a transformer and connected thereto through a blockage capacitor. Therefore,
The building's electrical system uses the parent equipment's 1.7MHz transmission frequency.
This results in a very complex antenna system for transmitting frequencies. The remote unit, as previously mentioned, has a transmit frequency near 49.8 MHz and typically includes a transmit-only telephoto antenna within its case. To receive the parent device's signal, the remote device typically has a loop rod antenna installed within the case. This ferrite loop antenna consists of a ferrite core wrapped with many wraps of very fine wire to form a co-op circuit at approximately 1.7 MHz and acts as an antenna to receive transmissions from the parent device.

The reason why a frequency of nearly 49.7 MHz is used for transmission by the remote device and a frequency of about 1.7 MHz is used for transmission from the parent device is that if the transmit frequency is very different from the receive frequency in a single device, , the proximity of the two antennas involved will cause most of the transmitted signal to be delivered to the front end of the nearby installed receiver, causing overloading and further damaging the circuit components. This is because it may lead to damage. Therefore, from about 47 MHz to 5
A separation of 0 MHz is adequate to prevent such interference. In this current system, the parent unit has a retractable whip antenna that is used only to receive transmissions from the remote unit, and uses the building wiring as an antenna for its own transmissions. The remote device, on the other hand, has a retractable whip antenna that is used only to transmit information to the parent station at its high transmission frequency, and also has an approximately 1.7 MH
It has a built-in ferrite loop antenna tuned to the Z transmission frequency. The frequency separation here is necessary, as already observed, in order to prevent the transmitted signal from being fed to the front end of a nearby installed receiver. The seven-elite loop antenna used in current cordless telephones suffers from inefficiency and even extreme directivity.

A transmission of about 50 MTlz used by a remote device is 1.7
It is interesting that the parent device can receive signals even further away than MHz transmissions. There are several reasons for this, one of which is that frequencies lower than 1 are more likely to be absorbed by wiring systems, receivers in the home, and other metal objects and electronic devices. It is also true that ferrite loop rod antennas are much less efficient than properly tuned whip antennas.

The transmission distance from the parent device depends on the size and configuration of the electrical system within the building, the amount of steel and other gold materials used in the building structure, and the glazed metal conduit through which the wiring inside the building is located. It is also true that the world is highly praised. When conduits are used to wrap the wiring, it becomes almost impossible to even get any transmission distance from the parent device, as the aerial # (building wiring system) will be completely wrapped in a grounded metal cover. .

Many different devices have been used to solve the problems that have arisen. Many of them either introduced new problems, solved only some of the problems that had arisen, or both. Many of the devices tested faced special requirements created by such special problems, and therefore
It can no longer be used for narrow purposes. Among other drawbacks of these prior art techniques, they either did not attenuate signals well or were severely distorted, making them unreliable for continuous use.
It was difficult to predict and expensive and complex to manufacture.

According to the present invention, a duplex communication system is provided that allows full duplex operation on closely spaced frequencies without the use of filters. Additionally, a portion of the transmitted energy is used to implement a first local oscillator at each station location to create an intermediate frequency.

According to the basic concept of the invention, at each station,
A portion of the local transmitter signal that can be compared in magnitude with the signal received from the remote transmitter and whose frequency differs from the remotely transmitted signal by means of an intermediate frequency is locally transmitted along with the received signal from the remote transmitter. Conversion (g) is added to the j path. Thus, each intermediate frequency signal modulated with information sent from a remote station is derived. This signal then
Processed to recover sent information.

In accordance with the illustrated embodiment of the invention, and in order to maintain this basic concept, at each station, simultaneously with the transmitted output signal, a cancellation, i.e., an image (no. The transmitted output signal and cancellation, i.e., each image, is
Thereby, a signal is simultaneously applied to the associated receiving device to supply the receiving circuit with a highly attenuated variant of the transmitted output signal;
This effectively generates each local oscillator number. In this way, in the receiving circuit, the received incoming signal and the weakened transmitted output signal are of a comparable magnitude,
Thereby, it becomes possible to generate a heterodyne effect that recovers the information, ie the audio signal, from the incoming signal.

Further advantages and features of the present invention will be apparent to those skilled in the art to which the invention pertains when reading the detailed description of the invention in conjunction with the accompanying drawings in which like reference numerals refer to like parts throughout. It will become even more clear.

Although specific embodiments of the present invention will now be described with reference to the drawings, such embodiments are for illustrative purposes only and are illustrated in the numerous possible applications that may represent the principles of the invention. It should be understood that only a small number of specific embodiments are illustrated. Various changes and modifications apparent to those skilled in the art to which this invention pertains are deemed to be within the spirit, scope and intent of the invention as further defined in the claims.

A close look at FIG. 1 examines the general operation of a conventional transmitter. The radio frequency oscillator 50 is a modulator/power amplifier 5
Generate input to 2. The audio input function, also numbered 53, provides a signal to an audio amplifier system 54 from which it is also applied to a modulator and power amplifier 52.

The combined output of the oscillator 50 and audio amplifier 54 generated in the modulator and power amplifier 52 is then provided to the transmitting antenna 10 for radiation into the air.

In FIG. 2, receiving antenna 10 receives a portion of the signal emitted from a conventional transmitter as described with respect to FIG. This tiny signal is applied to the front end circuitry of a conventional receiver, illustrated as radio frequency amplifier 55 in FIG. Radio frequency amplifier 55 provides its output signal to mixer 56, which also receives input from local oscillator 51, for generating an intermediate frequency. This intermediate frequency signal is supplied to an intermediate frequency amplifier 58 for amplification.

Signal detection to recover the received information is performed in a detector 59 that receives the amplified intermediate frequency signal from an intermediate frequency amplifier 58, and the detected signal is supplied to an audio frequency amplifier 60. be done.

This audio frequency signal is here amplified and fed to an output transducer 61, illustrated as a loudspeaker.

It was previously stated that the functions of transmitting and receiving voice information have been performed independently of each other.

However, various problems arise when attempting to combine these two functions in close physical proximity to each other, and further when attempting to use the same antenna for both transmitting and receiving.

Referring to FIG. 3, there is illustrated a square communication system of a particular type of conventional cordless telephone system which has a number of drawbacks which have been successfully attempted and resolved in accordance with the present invention.

All true cordless telephones usually operate in conjunction with a standard telephone system. Cordless telephones, as an example of a square communication system, should not be confused with non-Ivil telephones, even though the basic principles are the same. Modern cordless telephones simply provide devices, methods, and means to add to existing wireline telephone systems. As illustrated, the parent device 81 includes a parent receiver 72 and a parent transmitter T3 that are plugged into the lower 1 and connected together to the building's telephone system by a wired telephone connection cord 94. . This parent device is also connected to the building power system, labeled T4 by wired electrical connection cord 95. Although not specifically shown, cord 95 also connects the parent unit's transmitter to the building's wiring system, which acts as an antenna for the transmitter's transmit frequency, which is typically around 1.7 MHz. is used to. The parent station 81 also has a whip antenna 15, which has a frequency of approximately 49.9 MHz.
It has no purpose other than to receive signals transmitted from a remote mobile device 80 on its normal transmission frequency.

Remote mobile bag fi! , 80 consists of a transmitter 7T and a receiver 18. Due to the difference in transmission frequencies between the parent device and the mobile device, the remote mobile device has a remote receiving antenna T that receives the 1.7 MHz transmitted from the parent device 81.
9 and a remote transmitting antenna 16 for transmitting a 49.9 MHz remote transmitting signal to the parent station. It should be noted that parent station 81 and remote handheld device 80 each have antennas T5 and T6, which are conventional whip antennas.

Conventional whip antennas exhibit an omnidirectional radiation pattern. Referring to FIG. 4, the bipolar antenna 82
The radiation pattern 83 of FIG. Here, two bipolar confections are vertically arranged, and the resulting radiation pattern is donut-shaped, that is, annular. In general, a whip antenna consists of an upper part that is physically bipolar in shape and a lower bipolar part that is obtained as a reflected image from the ground. If we cut horizontally through the center of the torus 83, as shown by the dotted line 83a, we can see the ideal radiation pattern of the whip antenna, and thus its omnidirectionality. One of the problems addressed and solved by the present invention is the antenna problem. In the present invention, instead of using separate antennas for transmitting and receiving, the same whip antenna is used that performs both functions simultaneously.

To more clearly describe how the duplex communication system of the present invention differs from other full duplex communication systems operating at closely spaced frequencies, a portion of the locally transmitted signal energy is used as a first local oscillator. However, it would have been helpful to discuss the non-use of filters, a description of the problems involved, and previously contemplated solutions.

The performance of a full-duplex communication system is largely dependent on the ability to attenuate the effect of the local transmit power delivered to the antenna on the local receiver. In some current systems,
A switching function is performed to prevent transmitted signal energy from entering the front end of the local receiver; therefore, while this switching function is in effect, the local receiver cannot operate and a true duplex communication system is disabled. , not achieved.

If the operating frequencies of the transmitter and receiver are very different, for example, there is a 48.2 MHz frequency difference, such as 1.7 MHz and 49.9 MHz, the problems associated with this are very simple and easy to understand. However, if the two frequencies involved are 1% or 2% of each other,
If they differ by less than a percentage, the problem becomes very complex, especially if the same antenna is used for both transmit and receive functions. The main problem is that large transmitted signal energy is present at the front end of the receiver. This large transmitted energy present at the local receiver input terminals is reduced to an acceptable level, i.e., to a level that does not cause desensitization or overload damage to radio frequency amplifiers, converters, or intermediate frequency equipment. There must be. In many receivers, the level at which this is accepted is no more than a few millivolts L and therefore only a small percentage of each signal transmitted.

The standard solution to the problem of transmitter interference with the receiver is to use a filter at the receiver front end to pass the desired received signal and at the same time reduce the transmitted power, and also reduce the sensitivity of the receiver. To reduce fundamental band noise, a filter was used in the low power stage of the receiver.

In the dual cordless telephone communication system of the present invention illustrated in FIG. 5, station 62 is designated as the local station in the system and station 62' is designated as the remote station. Station 62 has an audio signal input to an audio frequency amplifier 63. The output of the audio amplifier 63 is the radio station'1 wave increase-).

It is coupled to a width gauge 65. Radio frequency oscillator/modulator 6
4 also supplies an input signal to the radio frequency amplifier 65. The output of radio frequency amplifier 65 increases the 4N level of the modulated radio frequency signal to the desired level before application to antenna 10. The output of radio frequency amplifier 65 is further coupled in turn to intermodulator 66 which is coupled to antenna 10.
is also combined with Antenna 1ot-x, working in both transmit and receive mode. Intermodulator 66 not only provides a signal from radio frequency amplifier 65 to antenna 10, but also provides an intermodulator between the signal from radio frequency amplifier 65 and the signal transmitted from remote station 62' and received by antenna 10. As a result of intermodulation, its internal output 22
Each intermediate frequency is also generated at 0. This intermediate frequency signal is fed to an intermediate frequency amplifier 6γ whose output signal is coupled to a demodulator 68. The output of demodulator 6B, ie the demodulated information sent from station 62', is coupled to an audio frequency amplifier 69 for amplification before being fed to a transducer, such as a loudspeaker.

At station 62', the remote station, the audio signal is received at the input to an audio frequency amplifier 63'. The amplified signal from audio frequency amplifier 63' is coupled to radio frequency amplifier 65'. A radio frequency carrier signal is provided by radio frequency oscillator/modulator 64' at a predetermined amount, ie, at a frequency offset from the carrier frequency of radio frequency oscillator 64 by an intermediate frequency. The output signal of the radio frequency amplifier 65' is varied by 1 to the level necessary for the antenna 10' to emit radio waves, as mentioned above.
Increase the level of the X+ radio frequency signal.

At this point, when referring to the same element on both the local station and the remote station, the same number may or may not have an apostrophe added to the right. It should be obvious that you are using it.

The signals received at the antenna 10 of the remote station 62' and the local station 62 are intermodulated with a controlled portion of the signal from the radio frequency amplifier 65 and the intermodulator 6
6 generates an intermediate frequency signal at the output terminal 220 of station 6, which is amplified by intermediate frequency amplifier 61 and then sent to demodulator 6 to restore the original information transmitted from station 62'.
Sent to 8th.

The anticipated operation of this system of the invention is described in the following. After amplification, each audio signal is applied to an audio frequency amplifier 63 which modulates a radio frequency carrier signal. After being amplified by the radio frequency amplifier 65, the amplified and modulated signal is then passed through the intermodal FJM unit 66 to the antenna 1.
0 and the modulated I signal is emitted, for example, at a nominal carrier frequency of 49.830 MHz.

A similar function is performed at station 62', except that the source of audio input to audio frequency amplifier 63' is the voice of the operator of that remote station.

The carrier signal of the radio frequency oscillator in the remote station is
For example, it has a frequency of 49.860 MHz, so that the signal transmitted from the airborne Ivjio' is a radio frequency signal, i.e. an audio signal derived from the voice of a remote operator, although the designation is 49.860 MHz. It is modulated.

At station 62, the 49.860 MHz incoming signal from station 62' is radio frequency amplified 2X.
65 to 49.830 MHz, thus producing a 30 KHz intermodulation signal.

This is the intermediate frequency signal appearing at terminal 220 of intermodulator 66. Intermediate frequency amplifier 671d, 30 KHz
and suitably amplify the modulated signal received from terminal 220. The intermediate frequency signal thus derived is demodulated in a demodulator 68 and the resulting audio frequency signal is amplified in an audio frequency amplifier 69 from which it can be used, for example, in a loudspeaker. Added to such audio converters.

The remote station is designated in this case station 6.
At 2', station 62 or 49.830MH
The incoming signal emitted at z is received by the antenna 1' and fed to the intermodulator 66', where:
It is named 49.860 MHz radio frequency amplifier 6
mixed with part of the signal from 5' and 30 KHz
The intermodulated signal appears at terminal 220' of intermodulator 66' and is passed from there to intermediate frequency amplifier 1567'. Additionally, the intermediate frequency signal appearing at terminal 220' is a 30 KHz signal modulated with an audio signal derived from the voice of the operator of station 62. The modulated intermediate frequency signal is amplified by a 30 KHz amplifier in intermediate frequency amplifier 67' and fed to a demodulator 68' from which audio signals are extracted and transmitted to an audio frequency amplifier 69' and thereafter. mJ is added to the converter as described above.

Because the system intermediate frequency amplifiers operate at different frequencies, a second remote station, such as station TO, can also use station 62' if it has a nominal frequency set of 49.890 MHz.

An examination of the conventional transmitter and receiver input circuits in FIGS. 6 and 7, respectively, is helpful in studying the preferred embodiment of the present invention. The output transformer 14 of a conventional transmitter has a tuned primary winding 13 connected to the supply voltage 15 and to the collector 18 of the output device transistor 1T. Usually 2 to 3 volumes of 2
The secondary winding 12 is then connected between ground and the antenna circuit, as shown in FIG. aerial line 10
is the secondary winding 12 of the transformer through the antenna tuning circuit 11.
It is connected to the. A signal source 21 provides an input signal to the base 20 of transistor 1T, and its emitter 19 is grounded as shown. The primary winding 13 of the transformer and the tuning capacitor 14 are connected in parallel between the voltage terminal 15 and the collector 18 of the transistor 1T.

This circuit is responsible for efficiently transmitting power to the antenna. If this membrane circuit configuration is used as the input circuit of a receiver, it is
Energy will be sent from the antenna to the cordless frequency amplifier 34. The signal energy received by the antenna 1o is sent to the primary winding 22 of the transformer 24 via the antenna tuning circuit 11. A tuned secondary winding consisting of a coil 23 and a capacitor 26 transfers No. 11 energy to the base 3 of the transistor 2T.
Send to ゜. The emitter 29 of the transistor 21 is grounded as shown. Collector 28 of transistor 2T
is a tuned circuit 3 consisting of a coil 32 and a capacitor 33.
Send signal energy to 1. Tuning circuit 31 is connected at terminal 25 to the power supply voltage.

Now referring to Figure 8, from basic transformer theory, if the output transformer 14 has two identical secondary windings, 12 and 12m, then the two secondary windings It can be seen that the voltages induced at both ends of the line are almost equal. If one of two identical secondary windings 12 is connected between the antenna circuit and earth, and the remaining secondary windings 12 & are connected in phase to the antenna circuit, one end is left unconnected to anything. Then, it becomes the form shown in FIG. What is important is that there is no difference in performance from the standard transformer circuit shown in FIG. If the remaining secondary winding 12a
If you measure the transmitted energy present between the unconnected end and ground, you will find that it is almost zero. It will not be exactly zero because there are slight differences between the two secondary windings and the extent to which they couple with the primary winding.

A direct connection to the antenna circuit can thus be achieved without the actual presence of transmission energy. By connecting the unconnected end of the secondary winding 12& to a tank circuit tuned to the receiving I-d frequency, as shown in FIG. It is possible to reach the optimal level. However, the illustrated bipolar connected transistor arrangement is not intended to limit or in any way reduce the generality of the invention as described above.

In FIG. 1O, a transmit signal generated in signal generator 21 is applied to transistor 400 base 20, and
Its emitter 19 is shown as being grounded. Collector 18 connects capacitor 1 to transmission transformer 14.
Transmission tuned at 6゛Output primary +il! It sends signal energy to 13.

The transformer output secondary winding 12 then supplies this transformer power to the antenna 10 through the antenna tuning circuit 11. Secondary winding 12a outputs almost the same signal as winding 12, but since the two windings are connected back to back, winding f112
There is only a very small transmit (i) signal energy at the bottom of &, therefore a very small transmit signal energy is sent by the coupling coil 36 to the tank circuit 3T of the converter 84,
It generates a highly attenuated form of the transmitted output 4m which is effectively a local oscillator signal.

When the signal is received on the antenna 10, it is
and is linked to tank circuit 37 by coupling coil 36 with very little transmit signal energy already present. As conventionally, transducer 84
It has a tank circuit 37, which itself consists of a tuning capacitor 39 with a coil 38. The output signal from the tank circuit 37 is supplied to the base 44 of the second transistor 41, the emitter 43 of which is grounded. The collector 42 of the transistor 41 is in turn connected to the transformer 4T, which in turn connects the tuned primary winding 4
5. Tuning capacitor 49. and a secondary winding 46. The power supply voltage is supplied at terminal 48. Thus, converter 84 generates an intermediate frequency signal representing the frequency of the difference between the transmitted frequency and the frequency of the received signal, while at the same time preventing undesired signal levels from entering the front end of the receiver from the transmitter. is prevented. Once again, the bipolar connected transistor arrangement illustrated herein is not intended to limit the invention.

FIG. 11 illustrates a second embodiment of canceling the transmitted signal within the input receiving circuit. The transmitted energy generated in tank circuit 180 is transferred to input transformer 182.
antenna loading coil 1 before being applied to tap 18γ of
81 first. Input transformer 182 has two winding sections, 183 and 184. First, winding part 1
83 has one end connected to the tap 181 and the other end connected to the antenna 1
Connected to 0. The twentieth lace section 184 is also connected to the tag 187 at one end and to the resonant circuit 185 at the other end. In this way, a portion of the transmitted signal energy flows in one direction through the input transformer 182 in the direction of the air a10 by the first winding portion 183. On the other hand, another part of the energy flows in the opposite direction through the input transformer 182 in the direction of the υ resonant circuit 185 by means of the second winding section 184 .

Therefore, a near-zero signal is applied to the secondary winding 18 of the input transformer 182 as a result of the incoming transmitted signal energy.
6, but a small portion of the transmitted WtJ energy of a size suitable for conversion appears.

When an incoming signal comes to the antenna 10, it is transferred to the input transformer 1
82. A very small portion of the antenna loading coil 1
81 and through the transmitter windings, but the resonant circuit 1
Because of 85, the amount of received signal energy in the path of antenna loading coil 181 is much less than the amount generated across receiver input windings 183 and 184.

The antenna loading coil is typically placed between the transmitter's signal energy source and the antenna. However, in this embodiment of the invention, the antenna loading coil was placed between the cancellation windings fIM 183 and 184 of input transformer 182 and the transmitter winding. This arrangement was effective in preventing the shunt capacitor from affecting the near-zero transmit signal induced in the secondary winding 186. The current difference is always common to both windings because the common source of current through the antenna loading coil is common to both windings. Therefore, the transmitted signal energy is approximately zero in the receiver tank circuit 186, and the received signal energy is induced in the receiver tank circuit winding 186, and the sum of their signals is It is generated through windings 183 and 184 where signal mixing takes place in a field effect transistor 188 of the converter. This field effect transistor configuration is not intended to limit the invention to that or any other particular method of performing signal conversion.

FIG. 12 shows another embodiment of the present invention, which uses a predetermined portion of a transmit signal of a constant nominal frequency that beats the incoming signal from a communication station to generate the desired intermediate frequency signal. It is possible. In FIG. 12, the example also shows that a constant frequency modulated signal generated at 111 of 9.860 MHz is applied to terminal 96;
It is applied to the base 9B of bipolar transistor 9T. The amplified signal with a nominal frequency of 49.860 lz appears at the collector 99 of transistor 97 and is fed to a coil tag 100 on a tank-coil 102, which is shunted by a tuning capacitor 104. There is. The operating voltage of transistor 91 is at terminal 10
It has been added through 1. Terminal 101 is shunted to ground through shunt capacitor 103. tank·
Coil 102. ! =liffJ capacitor 104 is designed to exhibit high impedance at a nominal frequency of 49.860 MHz. A tank circuit consisting of a tank e-coil 102 and a capacitor 104 is connected to a second transformer 1 through a first primary winding 114.
12 through a low impedance crosslink 105. The transformer 112 further has a second primary winding 116, which connects one end 106 to ground and the other end 10γ to the air &! 10. Transformer 11202
The next winding 109e is shunted by a capacitor 110, tuning it to a nominal frequency of 49.860 MHz. The Q of tank circuit 130 consisting of capacitor 110 and coil 109 is such that its half width is approximately 100 KHz. Because of this bandwidth, the tank circuit 130 is able to communicate with the feed signal generated by the oscillator 111 at a nominal frequency of 49.860 MHz, again for example at 49.860 MHz.
．． It accommodates both signals received by the antenna 10 with a nominal frequency of 830 MHz. The impedance looking into the tank circuit 130 is high, for example 100.000 ohms. Terminal 132 of tank circuit 130
is coupled to the gate 134 of field effect transistor 136, and the transistor has a high input impedance at gate 134. Terminal 131 of tank circuit 130 is coupled to terminal 118 of tank circuit 120, and the tank circuit consists of a tank coil 122 shunted by a tuned capacitor 123, the combination being tuned to a nominal frequency of 49.860 MHz. ing.

Again, tank circuit 120, like tank circuit 130, has a high impedance at the nominal frequency of oscillator 111. Tank coil 122 forms the secondary winding of transformer 125, and the transformer's primary winding 124 is
It is in the circuit from the emitter 113 of bipolar transistor 97 to ground. The emitter current at the oscillator 111 frequency is 180 degrees out of phase with the collector current at the oscillator 111 frequency.

The relationship between the windings of the tank circuit 120 and the tank circuit 130 is such that the frequency of the oscillator 111 appearing at the terminal 118 is 180 degrees out of phase with the signal of the same frequency appearing at the terminal 131 of the tank circuit 130. . therefore,
Gate 13 connected to terminal 132 of tank circuit 130
4 and ground, the signal approaches zero with the cancellation effects described above. 49.830 A crystal or magnetostrictive filter 1 is used to enhance the effective level of the signal received by the antenna 10 at the nominal frequency of z.
15 is coupled between terminal 131 of tank circuit 130 and ground. The device 115 costs only 3K)! passband 'f of Z: and it has, for example, 49.8
It is tuned to the frequency of the signal received by the 30 MHz antenna. In this way, the signal received from air #1110 is enhanced when applied to the gate 134 of field effect transistor mixer 136, while the signal #1L from oscillator 111 is transmitted to tank circuits 130 and 120.
It is attenuated to a level of 10 volts due to the cancellation effect between 16 received into the mixer 136 and the oscillator 111 before being used for heterodyne.
It is necessary to attenuate the signal from the receiver to obtain the mixer conversion element. It is well established that if the ratio of the two signals being mixed is too large, the effectiveness of the mixer is significantly reduced. Therefore, current cancellation methods are necessary and desirable to achieve efficient mixing and correct conversion gain. The output from the drain 135 of the field effect transistor 136 is passed through a carrier frequency trap 126 to J pairs of capacitors 12B and 129 at the desired intermediate frequency,
In this case it is coupled to a tank circuit 127 tuned to 30KHz. The glue actance of capacitor 128 is
At its operating frequency, it is less than the reactance of capacitor 129. The output to the intermediate frequency amplification transistor is taken from terminal 119. Terminal 117 is shunted to ground for radio frequencies by shunting capacitor 121. The source 133 of the lightning field effect transistor 136 is coupled to ground via a bias network 137.

Turning particular attention now to the fourth embodiment of the invention illustrated in FIG.
is received by antenna 10 at a nominal frequency of 9.860 MHz, and it is connected by conductor 138 to antenna combiner 139.
has been added to. The antenna combiner 139 also receives a signal input of a modulated signal, for example at a nominal frequency of 49.830 MHz, by means of a signal conductor 140 from a transmit power amplifier 141.

Amplifier 141 also provides its signal on conductor 142 to phase conversion circuit 143. The resulting 180 degree out-of-phase signals are applied to signal conductor 144 and capacitor 145 . This phase transformation is highlighted by the text in block 143 of FIG. At point 158 in FIG.
A signal of nominal frequency 1 and 1 are both present and applied to capacitor 146 by signal conductor 159. At the same time, in the example, transmission signal 1g with a nominal frequency of 49.830 MHz, but 180 degrees out of phase, is connected to signal conductor 1.
44 is added to the capacitor 145. In addition to being clearly 180 degrees out of phase, the two signals also have somewhat different widths, and in this way, the capacitor 14
The connected summation point 141 of 5 and 146 includes, in addition to the received signal, the locally transmitted signal that is attenuated by a factor that depends on the relative strengths of the applied in-phase and out-of-phase locally transmitted signals. You can see the number.

Referring to FIG. 14, a high level block diagram shows a transceiver/transducer 96 providing an output to an intermediate frequency amplifier 85.
is illustrated. The amplified intermediate frequency signal from intermediate frequency amplifier 85 is fed to some type of detector 86, as is conventional. In this way, the detector 86 generates a sound frequency signal, which is applied to a sound frequency amplifier 8T, the output of which is in turn applied to an output transducer 88, most commonly a loudspeaker. .

FIG. 15 consists of a capacitor 39 and a coil 38 with both the signal received from the antenna 10 and a portion of the transmitted signal from the transmit power amplifier 90.

The importance of the coupling coil 36 of FIG. 16 in providing the tank circuit 31 is emphasized. The transmission power amplifier 90 supplies its output (M energy) to the input/output tank, the antenna coupling circuit, and the transmitter phase cancellation circuit 89.The signal to be transmitted is then applied to the antenna 10, A portion is so-called leaked out by the coupling coil 36. The signal received by the antenna 10 is also sent to the coupling coil 36 and is applied to the tank circuit 3γ, where it is applied to the transducer 84, where it is generates an intermediate frequency resulting from the local transmitter frequency and the receiving year frequency. Again, as previously mentioned, this intermediate frequency signal is applied to an intermediate frequency amplifier 85 and then detected. 86 and an audio frequency amplifier 87 and finally to an output converter 88.

FIG. 16 illustrates an illustration of a full duplex communication system in which the two related transmission frequencies are 49.8
30 Ji4Hz and 49.860 MHz again. First transmitter/receiver station 9
1 includes an antenna operating at 10.49.830 MHz, a transmitter, and a receiver. A second transmitter/receiver station 92 has the same antenna 10.49.860
A transmission (iN) operating at WIz, including a receiver. Transmission from either station to the other generates an intermediate frequency of 30 KHz in the respective receiver. In either case, The local receiver will not be overwhelmed by the 11 signals from the local transmitter.
This is due to the unique circuit configuration of the present invention.

FIG. 17 illustrates an application example of the cordless telephone of the present invention 9. Parent transmitter/receiver (i-machine station 93 includes a parent receiver and a parent transmitter operating at, for example, 49.860 MHz. Att in the building via 11
i, wired to the talk system. 'This parent transmitter/receiver (i) is also wired to the building's electrical system 74 with a wired electrical connection cord 95. The building's electrical system, as in the prior art, It should be noted that it is not used as an antenna, which is no longer necessary due to the high frequency transmitted signals considered in the present invention compared to the low frequencies known in the prior art. The remote transmitter/receiver 91 has the same form as one of the receivers illustrated in FIG. Here, a transmit frequency of 49.830 MHz was illustrated such that an intermediate frequency of 30 KHz occurs between the two signals.As mentioned above, an additional transmit frequency of 49.890 MHz is used. Additional remote stations can also be implemented if desired.

In this way, a dual communication 1g system has been described, in which the two functions of signal transmission and signal reception can be performed simultaneously. Through the novel advantages of the present invention, significant improvements in communication convenience, ease of operation, and economy have been made.

The invention is illustrated in specific embodiments and includes:
Although having been described, it is to be pointed out that various changes and modifications apparent to those skilled in the art to which this invention pertains are nevertheless considered to be within the scope of this invention.

[Brief explanation of drawings]

FIG. 1 is a high-level block diagram of a conventional transmitter;
FIG. 3 is a high-level block diagram of a conventional cordless telephone parent and remote device; FIG. 4 is a high-level block diagram of a conventional cordless telephone parent and remote equipment; FIG. FIG. 5 is a block diagram of a dual communication (iW) system according to the present invention, FIG. 6 is a circuit diagram of a single transmitting circuit, FIG. 7 is a circuit diagram of a single receiving front end circuit, and FIG. Transformation 2
FIG. 9 is a circuit diagram of a portion of a single transmitter circuit showing that the two secondary coupled windings of a transformer are useful for developing an important embodiment of the present invention. Schematic diagram of the transformer circuit of Figure 8, Figure 1O shows that the wires are both connected to the antenna, but one winding is left unconnected at the other end. FIG. 11 is a circuit diagram of a combination of the circuit and the reception front end circuit, both coupled to an antenna according to the first embodiment of the present invention, and FIG. 12 is a circuit diagram showing the implementation of the second embodiment of the present invention. 13 is a circuit diagram illustrating the implementation of a third embodiment of the present invention, and FIG. 13 is a block diagram of one station according to the present invention useful for further explaining and highlighting the unique advantages of the present invention. , FIG. 14 is a high level block diagram of one station in the duplex communications system of the present invention, and FIG. 15 is a high level block diagram of one station highlighting the first embodiment of the duplex communications system of the present invention. Another high-level block diagram, FIG. 16, illustrates the general concept for implementing the invention, and FIG. 17 illustrates the general concept for the cordless telephone application of the invention. DESCRIPTION OF SYMBOLS 10... Antenna, 22... Primary winding, 24... Transformer, 36... Coupling coil, 31... Tank circuit,
47...Transformer, 51...Local oscillator, 66...
Intermodulator, 6T... intermediate frequency amplifier, 68... demodulator, 10... second remote station, 84... converter, 85... intermediate frequency amplifier, 108... antenna tuning coil , 120...tank circuit, 124...1
Next winding, 125...Transformer, 121...Tank circuit, 13o...Tank circuit, 14T...Total points, 18
o...Tank circuit, 185...Common camera circuit procedure Urasa 1':' (Spontaneous) Showa era [i8 year 7718 +, + q1 Agency Director Shinji Wakasugi Kazuo ('l'l'+ !'I office trial officer
1. Indication of the case 1985 Patent Application No. 85982 2. Name of the invention Method and device for duplex communication 3. Relationship with the case to correct the problem Applicant name Maxon Electronics Company Limited 4.
Agent 5-r+Ii City Order II Inquiry Showa Year Month; 11 (Voluntary) 6, Supplement i]: Target 1, Application - Name of Representative 1 2. Engravement of the entire specification (However, regarding the contents 3. Engraving of all drawings (However, there is no change in a) 4. Power of attorney and translation 7- Contents of Mli+l: 152-

Claims (1)

[Claims] 11) A method for simultaneously operating a communication device having a transmitting circuit, a receiving circuit, and an input/output circuit in both a transmitting mode and a receiving mode at different but close carrier frequencies, the method comprising: A signal is generated in a transmitter circuit and applied to an input circuit to generate an image signal of substantially equal magnitude and opposite phase at the same time as the generation of the transmitter output signal, and to generate an image signal of approximately equal magnitude and opposite phase, which is effectively a local oscillator signal. The transmit output signal and the image signal are combined to generate a weakened deformation, and the local oscillator signal is applied to a receiving circuit to generate a weakened deformation of Direct most of the incoming 4g to the receiving circuit so that the incoming signal coming into the circuit is of comparable magnitude, and then direct the incoming signal and the local part to recover the information carried in the incoming signal. A method as described above comprising the step of using a receiver circuit to effect heterodyning with the oscillating signal. (2) combining the transmitted output signal and the image signal to generate a highly weakened version of the output signal that is in effect a local oscillator signal, the step having a primary winding; a transmitting transformer having first and second substantially identical secondary windings, applying a transmitting output signal generated in the transmitting circuit of the first station to the primary winding; A coupling coil is provided having two ends, one end connected to said input/output circuit and the other end to a common circuit potential point, and one end of said 2nd secondary winding is connected to said input/output circuit, so that it is connected to said input/output circuit. in phase with the 12th winding, the other end of the 22nd winding is connected to one end of the coupling coil, and the other end of the coupling coil is connected to the common circuit potential point;
Accordingly, the coupling coil combines the transmission output (including a predetermined proportion of K) generated in the transmission circuit of the first station with the de facto local oscillation signal and the radio signal received from the second radio station. 2. The method of claim 1 comprising the steps of: (3) generating a highly attenuated variant of the output signal that is in effect a local oscillator signal; The step of combining with the image signal includes: generating a first radio frequency carrier signal of a predetermined frequency; applying the carrier signal to a first PI tuning tank circuit; coupling the first tuning tank circuit to a linking coil; A second tuned tank circuit is provided, the linking fist coil is coupled to both the second tuned tank circuit and the input/output circuit, and a second tuned tank circuit is provided with a first carrier signal having the predetermined frequency but in reverse phase with respect to the first carrier signal. two radio frequency carrier signals, and the second tank circuit includes a predetermined proportion of the transmit output signal generated in the transmit circuit of the first station;
Claims comprising the step of: transmitting said second carrier signal to said second tank circuit to include a composite signal that in effect generates a local oscillator signal and a radio signal received from said second radio station. The method according to the first term of the scope. (4) combining the transmitted output signal and the image signal to generate a highly attenuated variant of the output signal, which is in effect a local oscillator signal; a first tuned tank circuit, coupling the first tuned tank circuit to the input/output circuit, applying the first carrier signal to the first synchronized tank circuit, and coupling the first tuned tank circuit to the first synchronized tank circuit; coupled to a summation capacitor to generate a second radio frequency carrier signal at said predetermined frequency but in opposite phase with respect to said first carrier signal; in addition to a second tuned tank circuit, the second tuned tank circuit is coupled to a second summation capacitor, wherein the first carrier signal and the second carrier signal, which are in opposite phase with respect to the first carrier signal, are approximately connected to each other; cancel each other out,
coupling the first and second summing capacitors together at a summing point, providing a third tuned tank circuit, and providing a third tuned tank circuit for a very low signal value that effectively generates a local oscillator signal; includes a predetermined proportion of the transmitted output signal generated within the transmitting circuit of the first station;
a composite signal that effectively generates a local oscillator signal;
2. The method of claim 1 including the step of applying said sum to said third tuned tank circuit to include a radio signal received from a radio station. (5) The above transmitting circuit, receiving circuit, and input/output circuit are:
A second wireless station is installed in the first wireless station and further includes a second wireless station having 16 multi-transmission circuits, a receiving circuit, and an input/output circuit, and each station can operate both transmitting mode and receiving mode in different but close proximity. a second carrier frequency shifted by an intermediate frequency from the first carrier frequency transmitted by the transmitter circuit of the first radio station; In order to transmit a radio signal from the second radio station at a carrier frequency, the transmission output signal is applied to its input/output circuit, and the radio signal from the second radio station is received by the first radio station, In order to generate an intermediate frequency signal, a predetermined ratio of the transmission output signal generated at the second wireless station is combined with the MFR signal received from the first wireless station at the second wireless station. A method according to any preceding claim, such as mixing and then demodulating and using said signal at said intermediate frequency. (6) A communication station for use in a duplex communication system using different but close carrier frequencies,
The station includes: a transmitting circuit for generating radio frequency energy at a first carrier frequency; a receiving circuit including a demodulator; an antenna; and an intermodulation circuit coupled to the transmitting circuit, the receiving circuit, and the antenna; The intermodulation circuit is
producing a predetermined small fraction of the radio frequency energy generated by the transmitter, so that virtually all of the radio signal energy received by the antenna at the second carrier frequency powers the local oscillator into the receiving circuit. The communication station comprising the intermodulation circuit provided. (7) The intermodulation circuit includes a means for sending a transmission output signal from the transmission circuit to the antenna, a means for generating an image signal that is approximately equal in magnitude to the transmission output signal and completely opposite in phase, and a means that is effectively a local oscillator signal. means for summing said transmitted output signal and said image signal, said local oscillator (
if signal to the demodulator, and means for transmitting the signal received from the antenna to the demodulator, the difference between the transmit carrier frequency and the receive carrier frequency being equal to the intermediate frequency at which the demodulator is tuned. 7. A communication station as claimed in claim 6, in which the effective local oscillator signal has an energy level comparable to that of the received signal, so that efficient demodulation is achieved. (8) The intermodulation circuit includes a transformer having a primary winding and two substantially identical secondary windings, and the transmit output signal is coupled to the primary winding and the secondary winding One of the wires is coupled to the input/output circuit, and the two secondary windings are connected to a series loop circuit that generates a sum or difference signal from the two secondary windings. 8. A communication station as claimed in claim 7, including means for adding the same to said demodulation circuit. 9. A communication station according to claim 8, wherein said last-mentioned means include a winding having a reduced number of turns compared to said secondary winding. (10) All the communication stations according to claims 6 to 8 combined with a second communication station, wherein the second station is a transmitter that generates a radio signal on one of the carrier circumferential plates. a demodulator for receiving and processing intermediate frequency signals; an antenna for both receiving and transmitting radio signals; and means for transmitting a transmit output signal from the transmitting circuit of the second station to the antenna; means for generating an image signal equal in magnitude and opposite in phase to the output signal; an intermodulation circuit comprising means for summing the image signal, means for applying the local oscillator signal to the demodulator of the second station, and means for transmitting the signal received on the antenna to the demodulator; The difference between the transmit carrier frequency and the receive carrier frequency provides an intermediate frequency to which the demodulator of the second station is tuned, and the effective local oscillator signal has an energy level comparable to the energy of the receive signal. said communication station, whereby effective demodulation is achieved, said intermodulation circuit in each said station including means for coupling said transmitted radio signal to its associated antenna. αυ Each transmitter is coupled to its antenna by means of a transmitting transformer, each transmitting 4M transformer having a transmitting output primary winding, an sg1 transformer secondary winding, and a second transformer secondary winding. An antenna tuning circuit couples the first transformer secondary winding to the antenna to generate transmit output signal energy to the antenna, and a coupling coil connects the antenna to the antenna to generate a transmit output signal energy to the antenna. coupling the second transformer secondary winding to the intermodulation circuit to obtain a small portion of the energy and substantially all of the radio signal energy from a remote station to the intermodulation circuit received by the antenna; A device according to claim 9 or 1O, in which an intermediate frequency signal is derived. a coupler having a coupling coil connected to said antenna such that at least one of said intermodulation circuits is energized with signal energy received by said antenna; coupled to the coupling coil,
Thus, signal energy directed into the coupling coil is induced into the tank circuit, while at the same time signal energy received into the coupling coil from the transmitter is also induced into the tank circuit. The apparatus according to claims 9, 1θ, and 11. (131) at least one of the intermodulation circuits has a linking coil connected to the antenna so as to be energized with signal energy received on the antenna; Signal energy coupled to the coil and thus applied to the tank circuit is induced in the linking coil, while
At the same time, the signal energy received by the linking coil from the antenna is such that it is induced in the tank circuit.
Section equipment. 0 扲 Said summing means comprises a first summing circuit coupled to said generating means, a first summing capacitor coupled to said resonant circuit for receiving a radio frequency signal therefrom; a second summing capacitor coupled to the upper F tank circuit for receiving, said first and second summing capacitors electrically connected to form a summing point, and such that efficient frequency conversion is ensured. 14. The apparatus of claim 13 comprising a second resonant circuit connected to said summing point and responsive to all signals therefrom to generate a composite signal 4B having correlated signal component levels. ([51) All claims 6 through 14, wherein each of the demodulators includes an intermediate frequency amplifier coupled to its respective intermodulation circuit with each amplifier operating at the same intermediate frequency. (16) a first tank circuit in which the intermodulation circuit is responsive to the radio signal energy generated in the transmitter; a linking coil linking the first tank circuit to the antenna; a second tank circuit, linked to a linking coil, so as to sum the out-of-phase signal components to produce a much weakened variant of the transmitted signal, which is in effect a local excavation signal; a third tank circuit responsive to an opposite phase radio signal generated in the transmitter and connected to the second tank circuit; Along with the radio signal energy received by the antenna,
8. The device of claim 6 or claim 7, which in effect includes said local excavator. a first tank circuit responsive to the wireless signal energy generated in the transmitter; a first summation capacitor connected to the first tank circuit; a first summation capacitor connected to the first tank circuit; a second summing capacitor connected to said second summing capacitor and said second summing capacitor, said first summing capacitor and said second summing capacitor; or Apparatus according to paragraph 7.