JPH02246563A - Radio communication equipment - Google Patents

Abstract

PURPOSE:To make a normal communication even by a communication system which uses a modulated signal deviating in spectrum by a digital signal difficult in automatic frequency control by calibrating the frequency of a local oscillator by using a specific radio channel. CONSTITUTION:A radio equipment 30 has an antenna 32, and consequently a communication channel for plural information communications is inputted to an input terminal 1. Further, the radio equipment 30 inputs an error calibration radio channel to which a specific radio channel is assigned to the input terminal 1 so as to calibrate the error of the local oscillator 15. Namely, the radio channel for the frequency calibration is received before an information communication is made or when there is no communication and the output frequency of the local oscillator 15 is corrected into a specific frequency. Consequently, a narrow-band frequency division multiple access communication system whose reception band is, for example, <=1/100000 of the radio frequency is realized.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to frequency division multiple access (FDM^) modulating digital signals.
The present invention relates to a communication device using Multiple Access, and particularly to a wireless communication device that transmits digital signals in a narrower band than radio frequencies.

(Prior Art) A wireless communication device that is applied to a communication system in which the reception band is extremely narrow relative to the radio frequency needs to have an extremely small error in the oscillation frequency of a local oscillator within the device. For this reason, conventional wireless communication devices have been equipped with a constant temperature bath and a crystal oscillator installed therein to reduce the oscillation frequency error.

Also, for example, [Slip 1111PLL] by Kakinuma et al.
``Frequency stabilization technology using a crystal oscillator'', Proceedings of the 1986 IEICE Spring National Conference, describes a conventional technique that reduces the oscillation frequency error without placing the crystal oscillator in a thermostatic oven. That is, in this conventional technology, the temperature characteristics of the crystal oscillator are measured and stored in a memory circuit.
The stored contents are read out at a predetermined temperature and corrected by a frequency correction circuit.

(Problems to be Solved by the Invention) However, a device provided with a thermostatic chamber consumes a large amount of power, making it difficult to apply it in fields such as mobile communications where power consumption is limited as much as possible. In addition, with the conventional technology that stores the characteristics of the crystal oscillator in a memory circuit, even if it is possible to compensate for the temperature characteristics of the oscillation circuit, it cannot compensate for changes over time8. When a bias occurs, if the frequency of the local oscillator is controlled based on this signal, a problem arises in that one local oscillator is erroneously controlled in frequency.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks of the prior art and provide a wireless communication device that calibrates the frequency of a local oscillator using a predetermined wireless channel.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a wireless communication device using one frequency division multiple access, which receives a communication channel for transmitting communication information and a frequency calibration channel for calibrating the frequency. With means.

Outputs a local oscillator signal that selects these channels,
A local oscillation means for setting the frequency of the local oscillation signal by inputting the first signal and correcting the set frequency by inputting the second signal; and an intermediate frequency signal when receiving either the first calibration channel or the communication channel. error detection means for detecting an error in the local oscillation means by comparing the frequency of the local oscillation means with a reference frequency; storage means for storing the error value detected by the error detection means; and a second signal corresponding to the error value for local oscillation. and an error correction control means for outputting to the means.

Further, according to the present invention, in a wireless communication system in a wireless communication device that is frequency division multiple accessed and has local oscillation means of its own station, the local oscillation means A radio channel for frequency calibration is received, a frequency error of the local oscillation means is detected through the radio channel, the value of the detected frequency error is stored, and the output frequency of the local oscillation means is adjusted to a predetermined frequency using the stored frequency error value. Correct to.

(Function) According to the present invention, when no communication is being performed, a radio channel provided for one calibration is received, the frequency error of the local oscillation means of the own station is detected, and this error value is stored in the storage means. to be memorized. Then, the output frequency of the local oscillation means is corrected to a predetermined frequency based on the error value stored in the storage means during communication.

(Example) Next, an example of a wireless communication device according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, there is shown a functional block diagram of a receiving system as an embodiment of a wireless communication device according to the present invention. Note that in the figure, each component of the wireless communication device that is not directly related to this embodiment is omitted.

The wireless device 30 has an antenna 32 through which a plurality of communication channels for communicating information are input to an input terminal l. The wireless device 30 also has a local oscillator 1 of this device 30.
In order to calibrate the error of No. 5, an error calibration radio channel to which a predetermined radio channel is assigned is input to the input terminal l. This calibration radio channel transmits a signal such as an unmodulated carrier wave, from which the frequency of the reference oscillation source of the own station can be easily detected.

The device side of the input terminal l is connected to the input terminal 2 of the mixer 12. The mixer 12 also has an input terminal 5 connected to a local oscillator 15 from which it outputs a local oscillation signal SO. The mixer 12 is a frequency conversion circuit that extracts the intermediate frequency of the signals inputted from these input terminals and outputs it to the output terminal 4. Terminal 4 is connected to the input side of intermediate frequency amplifier 16. The intermediate frequency amplifier 16 is an amplification circuit that amplifies the received intermediate frequency, and outputs the amplified signal from the output terminal 7 to the inside of the device 30, for example.

The output side of the amplifier 16 is also branch-connected to the input terminal 8 of a one-frequency error detection circuit 18, and the amplified intermediate frequency is also sent to this detection circuit 18. The detection circuit 18 also has its input terminal 11 connected to a reference oscillation source lO of the local oscillator 15, which will be described later. The error detection circuit 18 includes an amplifier 1
This circuit detects a two-frequency error by inputting the signal input from 6 and the reference frequency signal Sf from oscillation source 10. The detection circuit 18 is connected to a storage circuit 20, and the detected frequency error signal is sent to this circuit 20. In addition,
The frequency error detection circuit I8 may be a two-way ordinary frequency discriminator, in which case the signal from the terminal 10 is not required.

The storage circuit 20 is a memory that stores the received frequency error signal, that is, the frequency error value. Memo+120 is connected to error correction circuit 22. The error correction circuit 22 is a correction circuit that corrects the oscillation frequency of the local oscillator 15. That is, the correction circuit 22 corrects the oscillation frequency of the synthesizer 14 (described later) of the local oscillator 15 by reading out the frequency error value stored in the memory (c) path 20.

The local oscillator 15 is composed of a reference oscillation source 1G and a synthesizer 14. The reference oscillation source 10 is a signal source such as a crystal oscillator, and its reference frequency Sf is input to the frequency error detection circuit 18 and the synthesizer 14. The synthesizer 14 is a frequency synthesizer that converts the reference frequency Sf manually input from the reference oscillation source IO into a frequency set by the channel control signal Sl, and outputs the frequency to the input terminal 5 of the mixer 12. Synthesizer 14 again. A correction signal S2 from the error correction circuit 22 corrects the frequency set by the control signal Sl.

For example, before performing information communication, the synthesizer 14 is instructed to switch to the radio channel for calibrating the 1 frequency error in order to correct the 1 local oscillation.
The Il signal St is added. Note that here, the frequency of the synthesizer 14 when the error calibration radio channel for calibrating the frequency error is selected is f2. The frequency error of the local oscillator 15 is re, and the frequency of the error calibration radio channel is fl.
shall be.

The mixer 12 mixes the frequency f1 of the signal of the error calibration radio channel and the local oscillation signal ((f2 + fe) of the synthesizer 14.
))!・SO) is input, and the intermediate frequency signal (Ll-
(f2+fe)) is output to terminal 4. The intermediate frequency amplifier 16 amplifies the intermediate frequency from the terminal 4 and outputs the intermediate frequency to the output terminal 7 right-shift frequency error detection circuit 18 . The error detection circuit 18 inputs the reference frequency signal Sf from the reference oscillation source 1O, and calculates the frequency 1! of the input signal. fl
-421÷fe) is compared with a reference value (rt-f2) converted from this reference frequency signal Sr to detect an error fe. When the error detection circuit 18 detects the error fe, it outputs the error value Df to the storage circuit 20 and stores it therein. The error correction circuit 22 corrects the frequency error of the synthesizer 14 by inputting the error value D from the memory 20.

When the frequency error correction is completed, the channel control signal Sl
is switched from the frequency error calibration radio channel to the radio channel for information communication.

When the information channel is selected, the error correction circuit 22 adjusts the synthesizer 1 based on the error value of in the memory 20.
outputs an error correction signal S2 corresponding to the oscillation frequency of 5;
The local oscillator 15 is controlled to output a predetermined oscillation frequency. Therefore, the mixer 12 can convert the signal of the information communication channel into an error-free intermediate frequency signal and output it to the intermediate frequency amplifier 16. In addition,
Such frequency error correction processing may of course be performed during non-information communication.

In this way, according to this embodiment, by switching to a predetermined radio channel for calibrating one frequency error before performing information communication or when there is no information communication such as during non-information communication, one local oscillator 15 is calibrated. It has been corrected. Therefore, when necessary information is communicated, normal communication is possible even with a communication method using a modulated signal with a biased spectrum due to a digital signal for which automatic frequency control is difficult.

(Effects of the Invention) According to the present invention, a predetermined radio channel for performing one frequency calibration is provided in a frequency division multiple access communication device, and this frequency calibration is performed before information communication or when there is no communication. Since the configuration is configured to receive the radio channel to be transmitted and correct the output frequency of one local oscillation means to a predetermined frequency, a narrowband frequency division multiple access communication system in which the reception band is, for example, 1/100000 or less with respect to the radio frequency is possible. realizable.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing an embodiment of a wireless communication device according to the present invention. Lord's,':''s! Reference oscillation source mixer synthesizer local oscillator intermediate frequency amplifier error detection circuit 20, , , memory 22° to 30°, error correction circuit, wireless communication device Patent applicant Oki Electric Industry Co., Ltd. Representative Takao Katori Maruyama Implementation of wireless communication device Figure 1

Claims (1)

[Claims] 1. In a wireless communication device using frequency division multiple access,
The apparatus comprises: a receiving means for receiving a communication channel for transmitting communication information and a frequency calibration channel for calibrating a frequency; outputting a local oscillation signal for selecting the channel;
a local oscillation means for setting the frequency of the local oscillation signal by inputting a second signal, and correcting the set frequency by inputting a second signal; and an intermediate frequency signal when receiving either the calibration channel or the communication channel. error detection means for detecting an error of the local oscillation means by comparing the frequency of the error value with a reference frequency; storage means for storing the error value; and outputting a second signal corresponding to the error value to the local oscillation means. What is claimed is: 1. A wireless communication device comprising: error correction control means. 2. In the device according to claim 1, the local oscillation means includes: a reference oscillation source that outputs a constant reference frequency; and a synthesizer that synthesizes a desired frequency by inputting a constant frequency from the reference oscillation source. A wireless communication device, wherein the synthesizer sets a frequency using a first signal and corrects the frequency using a second signal. 3. In a wireless communication system in a wireless communication device that is frequency-division multiple-connected and has local oscillation means of its own station, the method includes: activating the local oscillation means at a predetermined time either before performing information communication or during non-information communication. receive a radio channel for frequency calibration of the radio channel, detect a frequency error of the local oscillation means using the radio channel, store the value of the detected frequency error, and adjust the output of the local oscillation means according to the stored frequency error value. A wireless communication method characterized by correcting the frequency to a predetermined frequency.