JPH11122132A - Radio equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio equipment having high detection precision while keeping a reception power detection function within a broad dynamic range. SOLUTION: An intermediate frequency IF amplifier 10 detects reception power received from an antenna terminal and provides an output of a received signal strength indicator RSSI signal. The RSSI signal outputted from the IF amplifier 10 is given to plural system of amplifiers 21, 24 to adjust a gain and an offset adaptive to an input condition of an A/D converter 23 or waveform shaping sections 28, 29 consisting of LPFs 22, 25 whose time constant is made different to detect reception power. Interlock switches 26, 27 select the waveform shaping sections 28, 29 depending to the purpose.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio apparatus having a function of detecting reception power received at a receiving side, for example, a mobile phone, a mobile phone and its base station, and a wireless LAN.
Suitable for wireless communication fields such as AN.

[0002]

2. Description of the Related Art A conventional wireless device of this type will be described with reference to the drawings. FIG. 5 is a configuration diagram schematically showing a conventional wireless device. In the drawing, common elements for transmission / reception include an antenna 1 for transmitting / receiving a radio wave serving as a carrier, a band-pass filter 2 for blocking unnecessary frequencies during transmission / reception, and passing only the bands of all channels to be used, a direction of a transmission / reception signal. A circulator 3 for determining sex is provided.

[0003] First, the receiving side will be described. A received signal passing through the circulator 3 is provided with an attenuator 4 used for circuit protection and received power adjustment at the time of strong input, and a low noise amplifier 5 (hereinafter referred to as "amplifier") for amplifying a weak signal with low noise. ,
LNA: Described as Low Noise Amplifier)
Then, the signal passes through a band-pass filter 6 that blocks unnecessary radio waves at the time of reception and passes only the band of all channels to be used, and is input to the down converter 7. In the down converter 7, the carrier frequency is changed to a first intermediate frequency (hereinafter, IF:
Intermediate Frequency), and the converted first intermediate frequency is subjected to band-pass filter 8 to remove out-of-band components of the channel.
Further, the signal is converted to a second IF frequency by the down converter 9.

[0004] The second IF frequency is amplified by the IF amplifier 10 and the received power is detected. The detected reception power is a reception power detection signal (hereinafter, RSSI signal: Receive Signal) having a voltage value corresponding to the magnitude of the power.
(Indicated as Strength Indicator). Second IF amplified by IF amplifier 10
The received signal of the frequency is input to the demodulation unit 11 and the demodulation unit 11
Reproduces the baseband received data and the clock synchronized therewith. The reproduced received data and clock are sent to the control unit 20 which controls the timing of the radio unit, error correction, synchronization supplement, and the like.

On the other hand, RS output from IF amplifier 10
The SI signal is amplified and offset-adjusted by the amplifier 21 in order to adapt to the input condition of the A / D converter 23 in the next stage. The RSSI signal output from the amplifier 21 is applied to a low-pass filter 22 (hereinafter, LPF: Low Pass).
Filter), the noise component superimposed on the RSSI signal is removed, the waveform is shaped, and the waveform-shaped RS
The SI signal is A / D converted by the A / D converter 23 so that the SI signal can be taken into the control unit 20 as a digital signal.

On the transmitting side, a quadrature modulator 17
Then, the modulated signal is modulated by the baseband transmission data sent from the control unit 20, the IF amplifier 16 amplifies the modulated signal, and the up-converter 15 converts the modulated signal to the carrier frequency. Then, the modulated signal converted to the carrier frequency is
The signal is input to a preamplifier 13 via a band-pass filter 14 that blocks unnecessary frequencies during transmission and passes only the band of all channels used, and is amplified by the preamplifier 13 to an appropriate input power of the power amplifier 12 in the next stage. Further, the power is amplified to a desired transmission power by the power amplifier 12 and radiated as a transmission radio wave from the antenna 1 via the circulator 3 and the band-pass filter 2.

The local oscillation circuits 18 and 19 generate highly stable local oscillation signals used for frequency conversion and modulation / demodulation. The wireless device having such a configuration has a function of detecting the received power as disclosed in Japanese Patent Application Laid-Open No. 7-288485, and can monitor the received power over a wide dynamic range. In particular,
In a TDMA / TDD wireless device, this function is used at the time of carrying out a search for an empty channel or an empty slot.

[0008]

As described above, the radio wave input to the receiver of the wireless device is such that the received signal constantly fluctuates in a wide power range depending on the distance to the wireless device as the communication partner and the radio wave propagation environment. I have. Wireless devices are designed with a wide dynamic range so as to detect weak signals to strong input signals in such a radio wave propagation environment. However, for the purpose of monitoring with high accuracy in a narrow power detection range, for example, antenna abnormality detection for monitoring the state of the antenna connected to the wireless device, and transmission power monitoring for monitoring the transmission output on the reception side, as described above. Monitoring cannot be performed with high accuracy over a wide dynamic range.

An object of the present invention is to provide a radio apparatus having a high detection accuracy while maintaining a reception power detection function of a wide dynamic range in order to solve the above problems.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, a reception power detection section for detecting a reception power input from an antenna end and outputting the received power as an RSSI signal, A / D to convert to signal
A converter and an RSSI signal output by the received power detector are adapted to adapt to input conditions of the A / D converter.
A wireless device having a plurality of systems of amplifiers for adjusting a gain and an offset value, wherein a connection with the reception power detection unit is switched to any of the plurality of systems of amplifiers in response to a purpose of detecting reception power. It is characterized by comprising switching means.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a plurality of systems of low-pass filters having different time constants for removing noise components from the RSSI signal output from the received power detection unit, and reducing the received power. According to a feature of the present invention, a switching means for switching connection to the reception power detection unit to a plurality of systems of amplifiers and switching to one of the plurality of systems of low-pass filters is provided.

According to a third aspect of the present invention, in the first aspect of the present invention, the A / D converter is configured to be capable of changing the number of times of sampling of the received signal, and performs an averaging operation on the fetched digital signal to perform superposition. And a function of removing a noise component to be calculated.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. (Embodiment 1) A heterodyne wireless device employing a TDMA / TDD system will be described as a first embodiment.

The present embodiment has an antenna abnormality detecting function for monitoring the connection status of the antenna 1 at the time of transmission, and the reflected power at the antenna end is monitored by the IF amplifier 10 having the RSSI signal detecting function on the receiving side. It is realized by the method of doing. As shown in FIG. 1, this radio apparatus, as in the conventional example, has an antenna 1 as a common element for transmitting and receiving radio waves serving as carrier waves, and blocks unnecessary frequencies during transmission and reception.
The apparatus includes a band-pass filter 2 for passing only the bands of all channels to be used, and a circulator 3 for determining the directionality of a transmission / reception signal.

The reception side will be described. A reception signal passing through the circulator 3 is provided with an attenuator 4 used for circuit protection and reception power adjustment at the time of strong input, and a low noise amplifier 5 (hereinafter, LNA) for amplifying a weak signal with low noise. : L
ow Noise Amplifier) and a band-pass filter 6 that blocks unnecessary radio waves at the time of reception and passes only the band of all channels to be used, and inputs the down-converter 7 to the down-converter 7. In the downconverter 7, the carrier frequency is changed to a first intermediate frequency (hereinafter, IF: Inte
The converted first intermediate frequency is removed by a band-pass filter 8 to remove the out-of-band component of the channel, and further converted by a down converter 9 to a second IF frequency.

The second IF frequency is amplified by the IF amplifier 10 and the received power is detected. The detected reception power is a reception power detection signal (hereinafter, RSSI signal: Receive Signal) having a voltage value corresponding to the magnitude of the power.
(Indicated as Strength Indicator). Second IF amplified by IF amplifier 10
The received signal of the frequency is input to the demodulation unit 11 and the demodulation unit 11
Reproduces the baseband received data and the clock synchronized therewith. The reproduced received data and clock are sent to a control unit 20 that controls the timing of the radio unit, error correction, synchronization supplementation, and the like.

On the other hand, RSS output from IF amplifier 10
The I signal is input to the waveform shaping unit 28 or 29. The waveform shaping section 28 includes an amplifier 21 and an LPF 22, and the amplifier 21 outputs RSS output from the IF amplifier 10.
Amplification and offset adjustment are performed to adapt the I signal to the input condition of the A / D converter 23 in the next stage, and the LPF 22 removes a noise component superimposed on the RSSI signal and shapes the waveform.

Similarly, the waveform shaping section 29 includes an amplifier 24 and an LPF 25. The amplifier 24 has a larger gain than the amplifier 21, and converts the RSSI signal output from the IF amplifier 10 into an A / D converter at the next stage. Amplification and offset adjustment are performed to adapt to the input conditions of
Like the LPF 22, the PF 25 removes a noise component superimposed on the RSSI signal and shapes the waveform.
It has a time constant larger than that of F22 and can improve the accuracy of capturing the RSSI signal in combination with the amplifier 24.

Interlocking switches 26 and 27 interlocking with each other are inserted into the input / output terminals of these waveform shaping units 28 and 29, respectively, and a waveform shaping inserted between the A / D converter 23 and the IF amplifier 10 is provided. The unit can be selected by the switches 26 and 27 according to the purpose of detecting the received power. The RSSI signal shaped by the waveform shaping unit 28 or 29 is A / D converted by the A / D converter 23 so that the RSSI signal can be taken into the control unit 20 as a digital signal.

The amplifier 24 of the present invention performs amplification and offset adjustment to adapt the RSSI signal detected by the IF amplifier 10 to the input condition of the A / D converter 23 in the next stage, similarly to the amplifier 21. , And has a larger gain than the amplifier 21. The LPF 25 of the present invention is
It has a larger time constant than F22, and the accuracy of receiving the RSSI signal can be improved in combination with the amplifier 24. The amplifier 24 and the LPF 25 constitute a waveform shaping unit B29.

The interlock switches 26 and 27 switch between the waveform shaping unit A28 and the waveform shaping unit B29 of the RSSI signal to select an output signal to the A / D converter 23 at the next stage in accordance with the purpose of detecting the received power. The selected output signal is A / D-converted by the A / D converter 23 so that it can be taken into the control unit 20 as a digital signal. On the transmitting side, the quadrature modulator 17 modulates with the baseband transmission data sent from the controller 20, amplifies the modulated signal with the IF amplifier 16, and converts the modulated signal to the carrier frequency with the up-converter 15. Convert. The modulated signal converted to the carrier frequency is input to a preamplifier 13 via a band-pass filter 14 that blocks unnecessary frequencies during transmission and passes only the band of all channels used, and the preamplifier 13 outputs the modulated signal to the next stage. The power is amplified to an appropriate input power of the power amplifier 12, further amplified to a desired transmission power by the power amplifier 12, and the circulator 3 and the band-pass filter 2 are amplified.
And is radiated from the antenna 1 as transmission radio waves.

The local oscillation circuits 18 and 19 generate highly stable local oscillation signals used for frequency conversion and modulation / demodulation. In the present embodiment configured as described above, when monitoring the received power after the establishment of a carrier channel or a communication channel for searching for an empty channel or an empty slot, when the interlocking switches 26 and 27 are tilted toward the waveform shaping unit 28, An amplifier having a small gain and a wide dynamic range can monitor the received power over a wide dynamic range (AA ′ in FIG. 2A) so that the received power fluctuation caused by multipath, fading, and the like can be detected. .

Further, since the LPF 22 of the waveform shaping section 28 has a filter configuration having a small time constant, a received signal for each slot in which a burst operation is performed can be reliably monitored. Next, when performing antenna abnormality detection, as described above, the antenna abnormality detection employs a method in which the reflected power at the antenna end during transmission is converted into a voltage value by the IF amplifier 10 having the RSSI signal detection function on the receiving side. The circulator 3 is used to separate the reflection signal and the transmission signal input to the reception side, and the attenuator 4 is turned on at the time of transmission to protect the reception side.

Here, the transmission power input to the circulator 3 is Ptx (positive), the loss from the circulator 3 to the antenna 1 is L (positive), and the S parameter representing the magnitude of the reflected power with respect to the input power at the antenna end is: R (negative), the isolation of the port between the transmission and reception of the circulator 3 is I
If so (positive), the power range for detecting an antenna abnormality is (Ptx−L + R) − (Ptx−Iso) = Iso
+ (RL). According to this equation, the power range of the antenna abnormality detection is determined by the isolation of the circulator 3, and it is necessary to detect the reflected power in a narrow range as shown by BB 'in FIG.

Therefore, when the interlocking switches 26 and 27 are turned to the waveform shaping section 29, the amplifier 24 having a large gain and the LF having a large time constant so that a minute power fluctuation can be detected.
After the superimposed noise component is sufficiently removed by P25, the digital signal can be accurately taken in through the A / D converter 23. As described above, in the present embodiment, power detection that requires a wide dynamic range, such as carrier sensing and reception power monitoring, and power detection, which requires high accuracy in a narrow dynamic range, such as antenna abnormality detection, are simplified. It can be realized with a simple configuration.

(Embodiment 2) In this embodiment, FIG.
As shown in the figure, the configuration is substantially the same as that of the first embodiment, but the interlocking switches 26 and 27 switch the waveform shaping unit 30 and the waveform shaping unit 31 including only the amplifiers 21 and 24 having different gains, and The difference is that the LPF 24 is shared.

However, the number of times of sampling of the received signal in the A / D converter 23 can be freely controlled. For the purpose of detecting the received power, the number of times of sampling is changed and averaged with the taken digital signal. And the function of calculating the average value as shown in FIG. 3 (b). The operation of the main part of this embodiment will be described.

To monitor the received power after establishing a communication channel or carrier sense for searching for an empty channel or an empty slot, the interlocking switches 26 and 27 are set to the waveform shaping section 3.
It is tilted to the 0 side, and is monitored over a wide dynamic range (AA ′ in FIG. 4A) so that fluctuations in received power due to multipath, fading, etc. can be detected. Here, the LPF shared by the waveform shaping unit 30 and the waveform shaping unit B31
The filter 22 has a filter configuration having a small time constant because it is necessary to monitor the received signal for each slot.

Next, a case where the transmission power is monitored will be described. The transmission power input to circulator 3 is P
Assuming that tx and the isolation of the circulator 3 are Iso, the power of Ptx-Iso is input to the receiving side. Usually, since this power is excessively input to the receiving side, the attenuator 4 is turned on at the time of transmission. The power detection range for monitoring the transmission power on the receiving side is a narrow dynamic range (C-C in FIG. 4B) because the transmission power is known and the fluctuation range is very small.
C ') needs to be monitored. Therefore, the interlocking switches 26 and 27 are tilted toward the waveform shaping section 31 and amplified by the amplifier 24 having a large gain so that a minute power fluctuation can be detected.

A noise component is superimposed on the amplified signal with a non-negligible amplitude. The number of samplings of the A / D converter 23 is sufficiently increased within an allowable range, and the acquired data is averaged. LP with large time constant
F can perform the same function as noise removal. Therefore, in the present embodiment as well, power detection that requires a wide dynamic range such as carrier sense and reception power monitoring, and power detection that requires high accuracy in a narrow dynamic range such as transmission power monitoring are implemented with a simple configuration. It is possible to do.

Since other operations are the same as those of the first embodiment, the description of the operations is omitted, and the same components are denoted by the same reference numerals and symbols.

[0032]

According to the first aspect of the present invention, there is provided a reception power detection unit that detects reception power input from an antenna end and outputs the received power as an RSSI signal, an A / D converter that converts the RSSI signal into a digital signal, R output from the reception power detection unit
A wireless device having a plurality of systems of amplifiers for adjusting a gain and an offset value in order to adapt an SSI signal to an input condition of the A / D converter. Since switching means for switching the connection with the reception power detection unit to one of the amplifiers of the plurality of systems is provided, switching is performed between amplifiers having different gains in accordance with the purpose of detecting the reception power by the switching means. As a result, a plurality of dynamic ranges can be selected, so that the level can be correctly determined from detection of a reception power requiring a wide dynamic range to detection of a power failure requiring a narrow dynamic range such as an antenna abnormality detection and transmission power monitor. There is an effect that can be.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a plurality of systems of low-pass filters having different time constants for removing noise components from the RSSI signal output by the received power detecting section, and reducing the received power. Corresponding to the purpose of detection, while switching the connection with the received power detection unit to a plurality of systems of amplifiers, since it comprises a switching means for switching to any of the plurality of systems of low-pass filters,
In addition to selecting the dynamic range of the received power by switching the RSSI signal processing amplifier according to the invention of claim 1, the noise can be reduced even for applications requiring high accuracy, such as monitoring the received power of a burst signal and detecting an antenna abnormality. There is an effect that correct level determination can be performed while components are sufficiently removed.

According to a third aspect of the present invention, in the first aspect of the present invention, the A / D converter is configured to be capable of changing the number of times of sampling of the received signal, and performs an averaging operation on the fetched digital signal to perform superposition. Since it has a function to remove the noise component to be calculated in the calculation, instead of selecting a different time constant for the LPF for removing the noise component from the received signal detection signal,
2. The RSSI signal processing according to claim 1, without increasing the LPF, since the sampling number of the next-stage A / D converter can be changed and the averaging accuracy can be adjusted. In addition to selecting the dynamic range of the received power by switching the amplifier for use, it is also possible to remove the noise component sufficiently for applications that require high accuracy, such as monitoring the received power of burst signals and detecting antenna abnormalities, while maintaining the correct level. There is an effect that determination can be made.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a wireless device according to a first embodiment of the present invention.

FIG. 2A is an explanatory diagram illustrating a detection range of an RSSI level when detecting received power. (B) is an explanatory diagram showing a detection range of the RSSI level when detecting the transmission power.

FIG. 3A is a configuration diagram of a wireless device according to a second embodiment of the present invention. (B) is an explanatory diagram of averaging of sampling values of the NOA / D converter.

FIG. 4A is an explanatory diagram illustrating a detection range of an RSSI level when detecting received power. (B) is an explanatory diagram showing a detection range of the RSSI level when detecting the transmission power.

FIG. 5 is a configuration diagram of a conventional wireless device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 10, 16 IF amplifier 21, 24 Amplifier 22, 25 LPF 23 A / D converter 26, 27 Interlocking switch 28 Waveform shaping part 29 Waveform shaping part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Misawa 1048 Kazumasa Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd.

Claims (3)

[Claims] A reception power detection section for detecting reception power input from an antenna end and outputting the reception power as a reception power detection signal; and an A / D for converting the reception power detection signal into a digital signal.
A wireless device comprising: a converter; and a plurality of amplifiers that adjust a gain and an offset value in order to adapt a received power detection signal output by the received power detection unit to an input condition of the A / D converter. And a switching device for switching the connection with the reception power detection unit to one of the amplifiers of the plurality of systems for the purpose of detecting the reception power. 2. A system according to claim 1, further comprising a plurality of low-pass filters having different time constants for removing noise components from the reception power detection signal output by said reception power detection section. 2. The wireless device according to claim 1, further comprising a switching unit that switches connection to a reception power detection unit to the plurality of systems of amplifiers and switches to one of the plurality of systems of low-pass filters. 3. The A / D converter according to claim 1, wherein said A / D converter is configured to be able to change the number of times of sampling of the received signal. The A / D converter performs an averaging operation on the fetched digital signal and removes a superimposed noise component in the operation. The wireless device according to claim 1, comprising: