JPH0677913A - Returning system for radio transmission/reception equipment - Google Patents

Abstract

PURPOSE:To provide the returning function of a radio frequency by providing a passage to feed back a transmitting radio frequency signal to the input side of a receiving frequency converter, providing an intermediate frequency (IF signal switcher and outputting the two receiving IF signals of the receiving frequency converter while switching them. CONSTITUTION:The oscillating frequency of a local oscillator 41 is selected in the middle of a transmitting radio frequency and a receiving radio frequency so as to equalize transmitting and receiving frequencies. As a receiving signal converter 23, an image cancel frequency mixer is used for converting the receiving radio frequency signal and the image frequency of this signal to the IF signals respectively and outputting them, the passage is provided to feed back the transmitting frequency signal to the input side of the receiving frequency converter 23 while using a transmitting radio frequency signal distributor 15, receiving radio signal distributor 15 and receiving radio frequency signal coupler 25 at the time of returning, and the IF signals are outputted while being switched. Thus, the frequency of the transmitting IF signal is converted in a returning state, and the signal is outputted as the receiving IF signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal station folding method in a radio transmitter / receiver, and more particularly to a radio transmitter / receiver in which a transmitter local oscillator and a receiver local oscillator are shared.
The present invention relates to a loopback system of a wireless transmission / reception device, which enables loopback within a local station without using a frequency conversion device.

[0002] In recent years, in response to a demand for cost reduction of a wireless communication system, a transmitter local oscillator for transmitting frequency conversion and a receiver local unit for receiving frequency conversion, which have been used individually one by one, have been conventionally used. The method of reducing the number of oscillators to one by making the sum or difference of the transmission intermediate frequency and the reception intermediate frequency equal to the transmission / reception frequency interval which is the difference frequency of the transmission radio frequency and the reception radio frequency has come to be used. Came.

Further, in order to provide a line at a low cost, it is necessary to improve maintenance efficiency, and therefore, there is an increasing demand for facilitating equipment testing. In particular,
In a system in which the transmission frequency conversion unit and the reception frequency conversion unit in the wireless transmission / reception device are installed in the vicinity of the outdoor antenna to reduce the installation cost and power loss of the waveguide,
There is a demand for a loopback function within the maintenance station in order for the maintenance person to know the state of the wireless transmission / reception device outdoors while performing maintenance while staying indoors.

However, the radio transmission frequency and the radio reception frequency of one station are arranged on the frequency axis at regular intervals and multiplexed, and are usually different frequencies. Therefore, it cannot be folded back as it is, and it is necessary to perform frequency conversion so that the transmission frequency becomes the same as the reception frequency.

A frequency converter (shifter) for converting a transmission radio frequency signal into a reception radio frequency signal is generally used to perform such return in the own station. It is difficult to use such a frequency conversion device when a part of the wireless transmission / reception device is installed in the wireless communication device. Especially, in the case of a device in which the wireless transmission / reception device and the antenna are integrated, it becomes more problematic. .

When the local oscillators for transmission and reception are separate, it is possible to convert the transmission radio frequency to the reception intermediate frequency by changing the frequency of the reception side local oscillator. When the local oscillator and the receiving local oscillator are shared, it is impossible to change the local oscillation frequency only during reception.

Therefore, in a radio transmitter / receiver in which a transmitter local oscillator and a receiver local oscillator are used in common, it is possible to perform loopback within the own station without using a frequency converter.
There is a demand for a folding method of a wireless transmission / reception device.

[0008]

2. Description of the Related Art Conventionally, under such conditions, in order for a radio transmitter / receiver to perform a loopback in its own station, a loopback signal of a transmission radio frequency is transmitted at a local oscillation frequency shared with a reception frequency converter. A method is used in which the frequency is converted into the same frequency as the intermediate frequency, and the frequency is converted into a reception intermediate frequency by a second local oscillator having a sum or difference frequency of the transmission intermediate frequency and the reception intermediate frequency and a frequency conversion circuit.

FIG. 6 shows a conventional folding method, in which the transmission intermediate frequency signal input 10 and the reception intermediate frequency signal output 20 are mutually converted with the radio frequency signal of the radio frequency port 30. The method is illustrated.
In the figure, 11 is a transmission intermediate frequency circuit, 13 is a transmission frequency converter, 14 is a transmission radio frequency amplifier, 15 is a transmission radio frequency signal distributor, 16 is a transmission demultiplexing filter, 21 is a reception intermediate frequency circuit, and 22 is Intermediate frequency signal switcher, 23 is reception frequency converter, 24 is reception low noise power amplifier, 25
Is a reception radio frequency signal combiner, 26 is a reception demultiplexing filter, 31 is a duplexer, 41 is a local oscillator, 42 is a folding control circuit, 71 is a reception intermediate frequency distributor, 72 is an intermediate frequency converter, and 73 is an intermediate frequency converter. It is a frequency local oscillator.

On the transmission side, the transmission intermediate frequency signal input at 10 is transmitted from the transmission intermediate frequency signal in the transmission frequency converter 13 after being subjected to processing such as band limitation and power amplification in the transmission intermediate frequency circuit 11. Converted to radio frequency signals. After that, the power is amplified to a predetermined power by the transmission radio frequency amplifier 14, and a part of the power is branched by the transmission radio frequency signal distributor 15, and at the transmission / reception duplexer 31 via the transmission demultiplexing filter 16. Combined with the receiver signal and directed to the radio frequency port 30.

On the receiving side, the signal input from the radio frequency port 30 is applied from the duplexer 31 to the reception demultiplexing filter 26, separated from the signal on the transmission side, and then passed through the reception radio frequency signal combiner 25. The reception low noise power amplifier 24 performs low noise amplification, and the reception frequency converter 23 converts the reception radio frequency signal into a reception intermediate frequency signal.

The received intermediate frequency signal is distributed by the received intermediate frequency distributor 71 to the intermediate frequency signal switch 22 and the intermediate frequency converter 72. Normally, the signal that has passed through the intermediate frequency signal switch 22 is amplified by the receiving intermediate frequency circuit 21 to a predetermined power and output from the receiving intermediate frequency signal output 20.

At the time of turning back, the transmission radio frequency signal distributed from the transmission radio frequency signal distributor 15 passes through the reception radio frequency signal combiner 25, and then the reception low noise power amplifier 2 is received.
4. Since it is input to the reception frequency converter 23, a folding signal is generated at the output of the reception frequency converter 23 at a frequency different from the original reception intermediate frequency signal. The intermediate frequency converter 72 frequency-converts the output frequency of the reception frequency converter 23 into a predetermined reception intermediate frequency band using the local oscillation signal of the intermediate frequency local oscillator 73.

The intermediate frequency signal switch 22 performs switching under the control of the folding control circuit 42 to select the signal of the intermediate frequency converter 72 and input it to the reception intermediate frequency circuit 21. As a result, an intermediate frequency signal having a predetermined frequency is output to the reception intermediate frequency signal output 20, so that the internal station folding is performed.

[0015]

However, in the conventional folding method, the folding method is used only for the folding function.
It is necessary to incorporate a frequency conversion device including a local oscillator into a wireless device, which causes an obstacle to cost reduction and size reduction of the device, and the signal of the local oscillator not normally used leaks to the main signal. There was such a problem.

The present invention is intended to solve such a problem of the prior art, and in a radio transmitter / receiver in which a transmission local oscillator and a reception local oscillator are shared, without using a frequency conversion device, It is an object of the present invention to provide a loopback method for a wireless transmission / reception device, which is capable of loopback within its own station.

[0017]

Means for Solving the Problems (1) The present invention relates to a transmission frequency converter 13 for converting a transmission intermediate frequency signal into a transmission radio frequency signal, and a reception frequency conversion for converting a reception radio frequency signal into a reception intermediate frequency signal. In a wireless transmission / reception device equipped with a device 23 and only a local oscillator 41 for converting a transmission frequency and a reception frequency, the oscillation frequency of the local oscillator 41 is selected between the transmission radio frequency and the reception radio frequency, and transmission is performed. An image canceling frequency that equalizes the intermediate frequency and the reception intermediate frequency, and converts the reception radio frequency signal and the image frequency signal of the reception radio frequency signal into the reception intermediate frequency signal and outputs the reception radio frequency signal to the reception frequency converter 23. A mixer is used to provide a path for returning the transmission radio frequency signal at the time of folding back to the input side of the reception frequency converter 23, and An intermediate frequency signal switch 22 for switching and outputting the two received intermediate frequency signals of the converter 23 is provided.

(2) Further, in the present invention according to (1), the reception frequency converter 23 is provided in a path for returning the transmission radio frequency signal to the input side of the reception frequency converter 23 when the aliasing is not performed.
The radio frequency variable attenuator 51 for reducing the signal amount to the signal is provided.

(3) Further, in the present invention, in (1), a path is provided in which the transmission intermediate frequency signal is phase-inverted and returned to the output side of the reception frequency converter 23 when folding is not performed.

[0020]

(1) FIG. 1 shows the principle structure of the present invention, in which the same elements as in FIG. 6 are indicated by the same numbers. The wireless transmission / reception device which is a target of the present invention includes a transmission frequency converter 13, and a transmission intermediate frequency signal input 1
Convert the transmission intermediate frequency signal of 0 to a transmission radio frequency signal,
Output to the radio frequency port 30 via the duplexer 31,
Radio frequency port 30 with receive frequency converter 23
The reception radio frequency signal input from the transmission / reception duplexer 31 is converted into a reception intermediate frequency signal and is output to the reception intermediate frequency signal output 20. At this time, the transmission frequency conversion and the reception frequency conversion are performed. It has only one local oscillator 41.

In such a radio transmitter / receiver, the oscillation frequency of the local oscillator 41 is selected between the transmission radio frequency and the reception radio frequency so that the transmission intermediate frequency and the reception intermediate frequency become equal.

As the reception frequency converter 23, an image cancellation type frequency mixer which converts the reception radio frequency signal and the image frequency signal of the reception radio frequency signal into a reception intermediate frequency signal and outputs the reception intermediate frequency signal is used. By the transmission radio frequency signal distributor 15 and the reception radio frequency signal combiner 25, a path for returning the transmission radio frequency signal to the input side of the reception frequency converter 23 is provided, and the intermediate frequency signal switch 22 is provided. It is controlled by the loopback control circuit 42 so that the two reception intermediate frequency signals of the reception frequency converter 23 can be switched and output.

Therefore, according to the configuration of FIG. 1, during normal transmission and reception, the received radio frequency signal is frequency-converted and output as a reception intermediate frequency signal, and in the folded state, the transmission intermediate frequency signal is frequency converted. Since the transmitted radio frequency signal is converted into the reception intermediate frequency signal and is output, it is possible to perform the loopback within the own station.

(2) At this time, a radio frequency variable attenuator 51 is provided in the path for returning the transmission radio frequency signal to the input side of the reception frequency converter 23, and when the aliasing is not performed, the reception frequency converter 23 is fed. By reducing the amount of signal,
During normal transmission / reception operation, it is possible to prevent the intermediate frequency component based on the transmission radio frequency signal from being mixed with the intermediate frequency signal based on the reception radio frequency signal to cause interference.

(3) Further, at this time, when the aliasing is not performed, the phase of the transmission intermediate frequency signal is inverted and the reception frequency converter 2
By providing a path for returning to the output side of 3 and canceling the intermediate frequency component generated at the output of the reception frequency converter 23 based on the transmission radio frequency signal, the transmission radio frequency signal is converted into the transmission radio frequency signal during the normal transmission / reception operation. The intermediate frequency component based on the received radio frequency signal can be prevented from being mixed with the intermediate frequency signal based on the received radio frequency signal to cause interference.

In a radio apparatus having a single local oscillator that shares a transmitting local oscillator for converting the transmitting frequency and a receiving local oscillator for converting the receiving frequency, the sum or difference of the transmitting intermediate frequency and the receiving intermediate frequency is used. Is equal to the transmission / reception frequency interval, which is the difference frequency between the transmission radio frequency and the reception radio frequency, so the frequency of this local oscillator is selected to be between the transmission radio frequency and the reception radio frequency. And the reception intermediate frequency can be made equal. Therefore, if the transmission radio frequency is converted into the reception radio frequency by using such a local oscillation frequency, the return at the radio frequency becomes possible.

Generally, the receiving frequency converter is an image canceling type frequency mixer for suppressing a receiving image frequency signal existing at a frequency on the opposite side of the receiving radio frequency from the local oscillation frequency by the receiving intermediate frequency. Is used.

FIG. 2 shows an image cancellation type frequency mixer, in which 81 and 82 are hybrids,
83, 84, 85 are 90 ° hybrid (HYB), 8
6, 87, 88 and 89 are diodes and 90 is a 90 ° phase shifter.

Such image cancellation type frequency mixing
In the synthesizer, as is well known, the local oscillation frequency F_LO 
On the other hand, on the upper side, the reception intermediate frequency F_IFExist only apart
Signal F_S1(F_LO+ F_IF) And the reception intermediate frequency F on the lower side
_IFSignal F that exists only apart _S2(F_LO-F_IF) And from
Selectively picks up the received intermediate frequency signal based on one
Canceling the received intermediate frequency signal based on the other
Is possible. Image cancellation type frequency mixing
There are two such output signals at the two outputs of the
It occurs selectively.

For example, when a signal of 6.0 GHz is applied as a local oscillation signal to the input of the image cancellation type frequency mixer and an input signal of a radio frequency of 6.5 GHz is added, the frequency of the image cancellation type frequency mixer is 2%. One of the outputs outputs an intermediate frequency signal of 0.5 GHz generated by mixing a radio frequency signal of 6.5 GHz with a local oscillation signal of 6.0 GHz, and outputs the image frequency to the other output. The radio frequency signal of 5.5 GHz is 6.0 G
An intermediate frequency signal of 0.5 GHz generated by mixing with the local oscillation signal of Hz is output.

Therefore, by providing the intermediate frequency signal switching device for switching the output of the reception frequency converter, it is possible to take out the component in which the reception radio frequency signal is converted at the normal time and to transmit at the time of folding back. The component converted from the radio frequency signal can be extracted.

Therefore, according to the configuration of FIG. 1, the reception frequency conversion is performed by the local oscillation signal for both transmission and reception without providing the second local oscillation signal and the frequency converter for specially realizing the folding function. By doing so, it is possible to return from the transmission radio frequency signal to the reception radio frequency signal.

Since the intermediate frequency signal switch in this case has a low frequency, it can be constructed inexpensively and in a small size.
There are no restrictions on implementation.

[0034]

FIG. 3 shows an embodiment (1) of the present invention, in which the same parts as those in FIG. 6 are indicated by the same numbers, but the reception frequency converter 23 in this case has the same structure as described above. The image cancel type frequency mixer is used, and the intermediate frequency signal switching device 22 is different in that it selects two outputs of the image cancel type frequency mixer.

On the transmission side, the transmission intermediate frequency signal input at 10 is subjected to processing such as band limitation and power amplification in the transmission intermediate frequency circuit 11. Transmission intermediate frequency circuit 1
The output of 1 is applied to the transmission frequency converter 13 and is converted from the transmission intermediate frequency signal to the transmission radio frequency signal using the local oscillation signal of the local oscillator 41.

After that, the power is amplified to a predetermined power by the transmission radio frequency amplifier 14, and the transmission radio frequency signal distributor 1
5, a part of the electric power is branched, and the electric power is added to the transmission / reception duplexer 31 via the transmission demultiplexing filter 16.
Combined with the receiver signal and directed to the radio frequency port 30.

On the receiving side, the signal input from the radio frequency port 30 is applied to the receiving / demultiplexing filter 26 via the duplexer 31 and separated from the transmitting side signal.
It is added to the reception low noise power amplifier 24 through the reception radio frequency signal combiner 25 to perform low noise amplification, and is converted from the reception radio frequency signal to the reception intermediate frequency signal in the reception frequency converter 23.

Since the reception frequency converter 23 is composed of an image cancellation type frequency mixer, two reception frequency converters 23 are located above and below the local oscillation frequency (F _LO ) by a reception intermediate frequency (F _IF ), respectively. Signal (F _LO +
F _IF ) and (F _LO −F _IF ) generate reception intermediate frequency signals at the two outputs.

The intermediate frequency signal switch 22 is based on the signal from the loopback control circuit 42, and receives frequency converter 23.
One of the two outputs is selected. Reception intermediate frequency circuit 21
Outputs the received intermediate frequency signal output 20 after amplifying the selected received intermediate frequency signal to a predetermined power.

At this time, for example, if the transmission radio frequency signal is 6.
When the reception radio frequency signal is 5 GHz and the reception radio frequency signal is 5.5 GHz, the difference (transmission / reception interval) between the two is 1 GHz. Therefore, the frequency of the transmission intermediate frequency signal and the reception intermediate frequency signal is 1
If the frequency is 1/2 GHz, the local oscillation frequency will be 6.0 GHz because it suffices to be in the middle of the transmission radio frequency signal and the reception radio frequency signal.

Applying this to the case of FIG. 3, the oscillation frequency of the local oscillator 41 is 6.0 MHz, the transmission intermediate frequency at the transmission intermediate frequency signal input 10 is 0.5 GHz, and the transmission radio frequency at the output of the transmission frequency converter 13 is shown. Is 6.5
It becomes GHz.

On the receiving side, since the reception radio frequency is 5.5 GHz, the reception frequency converter 23 receives the 5.5 MHz signal, which is the original reception signal, from the transmission radio frequency signal distributor 15. The 6.5 MHz signal combined via the radio frequency signal combiner 25 is input, and 6.0 MHz is input as the local oscillation signal from the local oscillator 41.

At this time, the image canceling frequency mixer, as described above, outputs to one of the two outputs an intermediate frequency signal of 0.5 MHz obtained by frequency-converting the original received signal of 5.5 MHz. The output signal is output to the other side, and 6.5 MHz which is the aliasing component of the transmission signal is frequency converted to 0.
Outputs an intermediate frequency signal of 5 MHz.

Therefore, by the control signal from the loopback control circuit 42, the intermediate frequency signal switch 22 switches between the two inputs from the reception frequency converter 23.
The original received signal and the aliasing component of the transmitted signal can be selected and received.

As described above, according to the embodiment shown in FIG. 3, the normal transmission / reception operation is performed by the setting of the switching of the intermediate frequency signal switch 22, and the setting of the switching of the intermediate frequency signal switch 22 is changed. , It is possible to perform a loopback operation within the own station.

FIG. 4 shows an embodiment (2) of the present invention, in which the same parts as those in FIG. 3 are designated by the same reference numerals, and 51 is a radio frequency variable attenuator.

The image canceling type frequency mixer ideally cancels unnecessary signals by 100%, but after converting signals of each frequency to intermediate frequencies and then recombining them, the unnecessary components are canceled. In reality, it is not possible to completely cancel the unwanted component based on the imperfections of the circuit or device.

When the output power of the transmission radio frequency signal is high or when the input power of the reception radio frequency signal is low,
Since the level difference between the signals combined by the reception radio frequency signal combiner 25 becomes large, the non-cancellable component from one to the other becomes large, and the deterioration due to fixed interference increases.

In general, the transmission power is high, but the reception power is low and varies greatly depending on the spatial conditions.
Interference in the direction that the transmitted radio frequency signal gives to the original received signal becomes a problem.

In the embodiment of FIG. 4, a radio frequency variable attenuator 51 is provided to increase the amount of attenuation in the normal operation and decrease the amount of the attenuation in the return operation in accordance with the control signal from the folding control circuit 42. Such interference can be reduced by controlling so.

Since the radio frequency variable attenuator is generally large and expensive, it may affect the structure and cost of the apparatus. In this case, however, a method of canceling the interference component again at the reception intermediate frequency is equivalent. Conceivable.

FIG. 5 shows an embodiment (3) of the present invention, in which the same components as those in FIG. 3 are designated by the same reference numerals, 61 is a transmission intermediate frequency distributor, and 62 is an intermediate frequency signal variable phase. , 63 is an intermediate frequency signal variable attenuator, and 64 is an intermediate frequency signal synthesizer.

The intermediate-frequency signal variable phase shifter 62 and the intermediate-frequency signal variable attenuator 63 respond to the control signal from the folding control circuit 42 in the phase of the transmission intermediate-frequency signal distributed from the transmission intermediate-frequency distributor 61. By changing the delay amount and level fixedly or semi-fixedly, the intermediate frequency signal synthesizer 64 couples the transmission intermediate frequency signal thus distributed to the output of the intermediate frequency signal switcher 22.

During normal operation, the transmission intermediate frequency divider 61
→ Transmission frequency converter 13 → Transmission radio frequency amplifier 14 → Transmission radio frequency signal distributor 15 → Reception radio frequency signal combiner 25 → Reception low noise power amplifier 24 → Reception frequency converter 23 → Intermediate frequency signal switch 22 → Intermediate Frequency signal synthesizer 6
In the path of No. 4, the signal on the transmission side exists as a component that has not been canceled due to the above-described incomplete device.

Therefore, the intermediate frequency signal variable phase shifter 62 and the intermediate frequency signal variable attenuator 63 give amplitude changes and delays to the transmission intermediate frequency signal distributed by the transmission intermediate frequency distributor 61, and invert the phase. Then, the intermediate frequency signal synthesizer 64 synthesizes the above-mentioned signal on the transmission side and recombines it to reduce interference.

At the time of folding, the amount of the folding component is generally larger than the amount of the compensation component (the amount of the component that has not been canceled as described above), so that a problem is unlikely to occur as it is, but a control signal from the folding control circuit 42. By controlling the intermediate frequency signal variable phase shifter 62 and the intermediate frequency signal variable attenuator 63, the circuit may be configured to stop this compensation at the time of folding.
．

[0057]

As described above, according to the present invention, an intermediate frequency local oscillator and a frequency converter are newly added to perform folding in a radio transmitter / receiver in which a transmitter local oscillator and a receiver local oscillator are shared. It is possible to realize a folding function at a radio frequency without using.

Further, in the present invention, the compensation circuit is provided to cancel the leakage of the unnecessary component caused by using the image cancellation type frequency mixer to enable such operation. It is possible to prevent interference with the original received intermediate frequency signal when the aliasing is not performed.

[Brief description of drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention.

FIG. 2 is a diagram showing an image cancellation type frequency mixer.

FIG. 3 is a diagram showing an embodiment (1) of the present invention.

FIG. 4 is a diagram showing an embodiment (2) of the present invention.

FIG. 5 is a diagram showing an embodiment (3) of the present invention.

FIG. 6 is a diagram showing a conventional folding method.

[Explanation of symbols]

 13 transmission frequency converter 22 intermediate frequency signal switch 23 reception frequency converter 41 local oscillator

Claims (3)

[Claims] 1. A transmission frequency converter (13) for converting a transmission intermediate frequency signal into a transmission radio frequency signal and a reception frequency converter (2) for converting a reception radio frequency signal into a reception intermediate frequency signal.
3) and a unique local oscillator (41) for transmission frequency conversion and reception frequency conversion, the oscillation frequency of the local oscillator (41) is set between the transmission radio frequency and the reception radio frequency. The transmission intermediate frequency and the reception intermediate frequency are made equal, and the reception frequency converter (23) converts the reception radio frequency signal and the image frequency signal of the reception radio frequency signal into reception intermediate frequency signals. By using an image cancellation type frequency mixer that outputs the output, the transmission radio frequency signal at the time of folding back is received by the reception frequency converter (2
A radio wave characterized by being provided with a path for returning to the input side of 3), and provided with an intermediate frequency signal switching device (22) for switching and outputting two reception intermediate frequency signals of the receiving frequency converter (23). Folding method of transmitter and receiver. 2. The folding system of a radio transmitting / receiving apparatus according to claim 1, wherein the reception frequency is returned to a path for returning the transmission radio frequency signal to the input side of the reception frequency converter (23) when the folding is not performed. A folding system of a radio transmitter / receiver, comprising a radio frequency variable attenuator (51) for reducing a signal amount to a converter (23). 3. The folding system of the radio transmitter / receiver according to claim 1, wherein when the folding is not performed, a phase is provided for the transmission intermediate frequency signal to be phase-inverted and returned to the output side of the reception frequency converter (23). A method of folding a wireless transmission / reception device characterized in that