JP2003298432A - Transmitter and radio communication device provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To transmit a transmission signal in which a plurality of frequency bands exist without increasing the number of filters or without providing a changeover switch for the filters. <P>SOLUTION: Based upon the frequency band of the transmission signal, the generation frequency band of a first IF signal to be generated by a digital signal modulator 11a is adjusted to be matched with an upper frequency edge of a first IF band pass filter 14. Further, the oscillation frequency of a first local oscillator 24a is adjusted to match a second IF signal resulting from the conversion of the first IF signal by a first frequency converter 23a with a lower frequency edge of a second IF band pass filter 25. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter that modulates an input signal to convert it into a high frequency signal and transmits the high frequency signal in a desired frequency band, and a wireless communication apparatus including the transmitter.

[0002]

2. Description of the Related Art In recent years, a plurality of low-power wireless communication systems using the 5 GHz band, which do not require a license, have been proposed and standardized. Communication systems are being developed. However, the 5 GHz band has only four channels with a frequency band of 20 MHz (occupied signal frequency band is 18 MHz), and when many wireless communication terminals or a plurality of communication systems exist in the same area,
There is a high possibility that throughput will decrease due to interference. Further, basically, only one channel is used as a communication channel, and it is not assumed that a plurality of channels are bundled at the same time to carry out a large capacity communication.

In order to solve such a problem, a low power radio communication system using a quasi-millimeter wave band of 25 GHz band or 27 GHz band has recently been permitted under the Radio Law and standardization has been advanced. ing. For example, a personal area system designed for outdoor Internet access at hot spots such as stations and coffee shops is 24.77 GHz.
To 25.23 GHz (excluding guard bands of 20 MHz above and below) are used, and 23 wireless channels can be arranged at a frequency interval of 20 MHz (occupied signal frequency band per channel is 18 MHz). Simultaneous transmission of channels or less is possible. Furthermore, from 27.02 GHz to 27.46 GHz
(Excluding upper and lower 20 MHz guard bands)
In a community area assuming a wireless LAN or a wireless home link in a home or a factory, 22 wireless channels can be arranged at a frequency of 20 MHz and 6 channels or less can be simultaneously transmitted.

In such a communication system in which simultaneous transmission of a plurality of channels is permitted, the frequency band of radio signals is not constant. This means that filters used in transmitters, especially filters that require a steep attenuation characteristic for the purpose of preventing transmission of interfering waves to adjacent channels (SAW filters, etc.) The characteristics need to be changed. For example, when there are three types of frequency bands of wireless signals, at least three types of filters having different pass frequency bands are required in the IF frequency band and the baseband frequency band. The transmitter shown in FIG. 7 is considered as an example of the transmitter provided with such a filter according to the frequency band of a radio signal.

The transmitting apparatus shown in FIG. 7 includes a signal modulating section 10c, a first IF transmitting section 120, a second IF transmitting section 130, and an RF.
The transmission unit 40, the transmission / reception antenna 50, and the control unit 170 are included.

The digital signal modulator 11c having a transmission signal generating means generates a first IF signal based on the information of the frequency band of the transmission signal transmitted by the control section 170. The first IF signal is subjected to removal of unnecessary harmonic components such as a second harmonic wave and a third harmonic wave by the digital filter 12c, and is converted from a digital signal to an analog signal by the D / A converter 13c.

Here, the digital filter 12c is
Switching the characteristics of the filter according to the frequency band of the signal does not increase the number of parts or the development and manufacturing cost as characteristics of the digital circuit compared to the analog filter.
Due to the sampling frequency and the like, it is impossible to remove all unnecessary high frequency components. Therefore, an analog filter is required further downstream.

Next, the signal path of the analog first IF signal is switched according to the frequency band by the action of the first IF signal switch 127a, and the first IF band pass filter (from 121-1). 122-n). After the passage, the first IF signal is the first IF signal switch 127b.
Via the first IF transmission amplifier 122, the signal power is amplified to a signal power suitable for the input of the first frequency converter 123.

In the first frequency converter 123, the first IF signal is up-converted into the second IF signal by the local signal (frequency is fixed) input from the first local oscillator 124. The second IF signal is the second
The signal path is switched according to the frequency band by the action of the IF signal switch 128a, and passes through any one of the second IF band pass filters (129-1 to 129-n). After that passage, the second I
The F signal is transmitted through the second IF signal switch 128b to the second IF transmission amplifier 132 having a transmission power control function.
Then, it is amplified to a signal power suitable for the input of the second frequency converter 133.

Next, the second frequency converter 133
The second IF signal is up-converted into the RF signal by inputting the local signal generated from the local oscillator 134 of. Here, the control unit 170 controls the generation frequency of the local signal generated by the second local oscillator 134 to adapt the frequency band of the RF signal to the desired transmission channel.

Next, the RF signal is transmitted to the second frequency converter 1.
It passes through a wide band RF band pass filter 135 that passes the signal frequency bands of all channels for the purpose of removing the transmission spurious generated by 33. Then the RF signal is
It is amplified to a predetermined transmission power by the RF power amplifier 42 and is radiated into the air from the transmission / reception antenna 50 via the transmission / reception switch 43 and the RF bandpass filter 44.

[0012]

However, the transmitter of FIG. 7 described in the section of the prior art requires filters having different characteristics depending on the number of frequency bands of the transmission signal. That is, a communication system having three frequency bands (3 channel specifications) requires at least three filters with different characteristics, and a communication system having 6 frequency bands (6 channel specifications) requires at least 6 different characteristics. A characteristic filter is required.

Furthermore, in order to switch a plurality of filters, the switch circuit must have at least 2 in order to perform transmission impedance leakage to other signal paths and stable impedance matching with the circuits connected in the preceding and following stages. Individuals are needed.
In the configuration of FIG. 7, since the transmission signal is up-converted in two steps, the number of switches and the number of filters are doubled. 6 channel specification, at least filter 12
The number of switches (two sets of filters having 6 types of different characteristics) and four switch circuits are necessary for transmitting signals in a plurality of frequency bands.

This requires an extra filter and switch circuit, which not only increases the manufacturing cost, but also
There is a demerit that the mounting area increases when the transmitter is mounted on a small portable device. Furthermore, developing filters with different characteristics not only increases the development cost, but also makes it difficult to obtain uniform attenuation characteristics among different types of filters, which causes variations in transmission performance for each frequency band of the transmission signal. There is also the problem of being lost.

Therefore, in view of the above problems, the object of the present invention is to increase the number of filters for removing unnecessary radiation such as spurious signals of a transmission signal for the purpose of transmitting signals in a plurality of frequency bands. In particular, it is to provide a transmitter capable of transmitting radio signals in a plurality of frequency bands and a radio communication device using the transmitter without providing a switch circuit for switching the filter.

[0016]

In order to solve the above-mentioned problems, a first aspect of the present invention is to provide an input signal in a first frequency band within a predetermined frequency band.
Of the intermediate frequency signal, an IF conversion unit for converting the first intermediate frequency signal into a high frequency signal, an RF transmission unit for transmitting the high frequency signal, and a control unit for controlling each unit. In the transmitting device, the modulation unit includes the first
Of the intermediate frequency signal, and the first IF filter for passing the first intermediate frequency signal, the control unit, to the edge of the pass frequency band of the first IF filter The frequency of the modulator is adjusted and set so that the edges of the frequency band of the first intermediate frequency signal are aligned.

A second invention is the transmitting apparatus according to the first invention, wherein the IF converter converts the first intermediate frequency signal modulated by the modulator into a second intermediate frequency signal. A first IF including a first frequency conversion unit that performs the above, and a second IF filter that allows the second intermediate frequency signal to pass therethrough.
The control unit includes a conversion unit and a second IF conversion unit that includes a second frequency conversion unit that converts the second intermediate frequency signal into a high-frequency signal, and the control unit includes the pass frequency of the first IF filter. The frequency of the modulator is adjusted and set so that the edge of the frequency band of the first intermediate frequency signal is aligned with the edge of the band, and the edge of the second intermediate frequency signal of the second intermediate frequency signal is adjusted to the edge of the pass frequency band of the second filter. The frequency of the first frequency conversion means is adjusted and set so that the edges of the frequency band are aligned.

A third invention is the transmitting apparatus according to the first or second invention, wherein the modulating section includes a digital filter for removing unnecessary harmonic components of the intermediate frequency signal, and D / A conversion means for converting the pass signal of the digital filter into an analog signal, and the control unit aligns the edge of the frequency band of the first intermediate frequency signal with the edge of the pass frequency band of the digital filter. It is characterized in that the frequency of the modulator is adjusted and set.

A fourth invention is the transmitting apparatus according to the first, second or third invention, wherein the first IF filter is a bandpass filter or a lowpass filter.

A fifth aspect of the present invention is the transmitting apparatus according to the third aspect, wherein the digital filter is a digital filter having a bandpass filter or a lowpass filter function.

A sixth invention is the transmitting apparatus according to the second or third invention, wherein the second IF filter is a bandpass filter or a highpass filter.

According to a seventh aspect of the present invention, a modulator for modulating an input signal into a baseband signal in a predetermined frequency band, an IF converter for converting the baseband signal into an intermediate frequency or into a high frequency signal, A transmitter comprising an RF transmitter that transmits a high-frequency signal and a controller that controls each unit, wherein the modulator includes a signal modulator that modulates the baseband signal and the baseband signal. And a control unit that adjusts and sets the frequency of the modulation unit so that the edge of the frequency band of the baseband signal is aligned with the edge of the pass frequency band of the baseband filter. To do.

An eighth invention is the transmitter according to the seventh invention, wherein the IF converter converts the baseband signal modulated by the modulator into an intermediate frequency signal. Means and an IF for passing the intermediate frequency signal
A first IF conversion section including a filter; and a second IF conversion section including second frequency conversion means for converting the intermediate frequency signal into a high frequency signal, wherein the control section includes the baseband. The frequency of the modulator is adjusted and set so that the edge of the frequency band of the baseband signal is aligned with the edge of the frequency band of the filter, and the edge of the frequency band of the intermediate frequency signal is set to the edge of the frequency band of the IF filter. The frequency of the first frequency conversion means is adjusted and set so that

A ninth invention is the transmitting apparatus according to the seventh or the eighth invention, wherein the modulator includes a digital filter for removing unnecessary harmonic components of the baseband signal, D / A conversion means for converting a pass signal of the digital filter into an analog signal, and the control unit modulates the edge of the frequency band of the baseband signal to the edge of the pass frequency band of the digital filter. It is characterized in that the frequency of the section is adjusted and set.

A tenth aspect of the present invention is the transmitting apparatus according to the seventh, eighth or ninth aspect of the invention, wherein the baseband filter is a low pass filter.

An eleventh invention is the transmission apparatus according to the ninth invention, characterized in that the digital filter is a digital filter having a function of a low-pass filter.

A twelfth invention is the transmitting apparatus according to the seventh or eighth invention, wherein the IF filter is a bandpass filter or a highpass filter.

[0028] A thirteenth invention is a radio communication apparatus comprising the transmitting apparatus according to any one of the first to twelfth inventions.

In the present invention, the frequency of the local signal of the signal modulating means or the frequency converting means is adjusted and set so that the edge of the frequency band of the intermediate frequency signal or the base band signal is aligned with the edge of the pass frequency band of the filter. Unlike the conventional case, it is not necessary to prepare a filter having a different pass frequency band for each channel. This is because the noise component can be removed by moving the frequency band of the intermediate frequency signal and passing it through a filter having a predetermined pass frequency band.

For example, when modulating the input signal in the modulator, the upper limit frequency of the modulated signal in the first intermediate frequency band is the first
In addition to aligning with the upper edge of the IF filter, the pass frequency band of the digital filter is adjusted according to the frequency band of the modulation signal. The first filter removes harmonic noise components, such as a second harmonic wave and a third harmonic wave, which cannot be removed by the digital filter generated in the process of modulating a signal. Furthermore, by adjusting the conversion frequency of the frequency conversion circuit breaker, the lower limit frequency of the transmission signal in the second IF frequency band is aligned with the lower edge of the second filter, and Noise such as image components existing in the frequency band is removed.

When the input signal is modulated by the signal modulating means, the upper limit frequency of the modulated signal in the baseband frequency band is aligned with the edge of the baseband filter, and the frequency band of the modulated signal is adjusted. Depending on,
Adjust the pass band of the digital filter. The baseband filter removes harmonic noise components, such as the second harmonic wave and the third harmonic wave, which cannot be completely removed during the signal modulation process.

Further, by adjusting the conversion frequency of the frequency conversion means, the lower limit frequency of the transmission signal in the second intermediate frequency band is aligned with the lower edge of the IF filter, and the lower side of the transmission signal is adjusted. Noise such as image components existing in the frequency band of is removed. As a result, the above problem can be solved.

As described above, as a means for solving the problem of the present invention, the method of cutting the noise component by using each filter has been described. However, the problem can be solved even when there is no digital filter. There may be a plurality of first IF conversion units, and there is no problem, and only the necessary number is required to remove the noise of the intermediate frequency signal.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 is a block diagram showing the arrangement of a transmitting apparatus according to the first embodiment. The transmitter according to the first embodiment of the present invention includes a signal modulator 10a, a first IF transmitter 20a, a second IF transmitter 30, an RF transmitter 40, a transmitting / receiving antenna 50, and a controller 70a. Has been done. The configurations and functions of the RF transmitter 40 and the transmitting / receiving antenna 50 are the same as those of the example of the transmitter shown in FIG. 7, except that the signal modulator 10a and the first I
F transmission unit 20a, second IF transmission unit 30, control unit 70a
Is different from the example of the transmitter shown in FIG.

The digital signal modulator 11a provided with the transmission signal modulating means generates the first IF signal based on the information on the frequency band of the transmission signal transmitted by the control section 70a. The first IF signal has a digital filter 12a having a bandpass filter or a lowpass filter function to remove unnecessary harmonic components such as a second harmonic wave and a third harmonic wave, and a D / A converter 13a converts the digital signal from an analog signal to an analog signal. Is converted to.

Next, the analog-converted first IF signal passes through the first IF bandpass filter 14 to obtain the first IF signal.
In the IF transmission amplifier 22, the signal power suitable for the input of the first frequency converter 23a is amplified.

In the first frequency converter 23a, the first IF signal is up-converted into the second IF signal by the local signal input from the first local oscillator 24a. The up-converted second IF signal passes through the second IF band pass filter 25 and is transmitted by the second IF transmission amplifier 32 having a transmission power control function.
It is amplified to a signal power suitable for the input of the second frequency converter 33. The second frequency converter 33 inputs the local signal generated from the second local oscillator 34,
Up-convert the second IF signal to an RF signal.

Next, the RF signal is transmitted to the second frequency converter 3
The signal passes through a wide band RF band pass filter 35 that passes the signal frequency bands of all channels, which also has the purpose of removing the transmission spurious generated by the signal No. 3. After that, the RF signal is RF
It is amplified to a predetermined transmission power by the power amplifier 42, and is radiated into the air from the transmission / reception antenna 50 via the transmission / reception switch 43 and the RF bandpass filter 44.

The control section 70a is generated by the digital signal modulator 11a based on the frequency band of the transmission signal so that the upper limit of the frequency band of the transmission signal comes to the upper edge of the first IF bandpass filter 14. The frequency of the transmission signal is adjusted, and the pass frequency band of the first digital filter 12a is adjusted according to the frequency band of the modulation signal. Furthermore, the control unit 70a controls the oscillation frequency of the first local oscillator 24a based on the frequency band of the transmission signal so that the lower limit of the frequency band of the transmission signal comes to the lower edge of the second IF bandpass filter 25. Adjust. In addition, the control unit 7
0a is a transmission / reception switch 43 or a second IF transmission amplifier 32.
It also takes charge of overall control of the transmission device such as gain adjustment.

FIG. 2 is a flow chart relating to the transmitting method of the transmitting apparatus according to the first embodiment of the present invention,
FIG. 3 is a diagram showing an example of a transmission signal frequency characteristic of an embodiment according to the present invention on a frequency axis, and FIG. 4 is an example of a correlation between a filter and a transmission signal according to the first embodiment of the present invention. It is the figure which showed on the frequency axis. The transmission method of the transmission apparatus according to the present invention will be described below mainly with reference to FIG. 2 and also with reference to FIGS. 1, 3 and 4 as appropriate.

In the present embodiment, as shown in FIG.
Signals in three frequency bands as shown in (b) and (c) are used. FIG. 3A shows a transmission signal when only one channel is used, the center frequency of the transmission signal is fc, and the frequency band is 2Δf (Δf is the half width of the frequency band of one channel). FIG. 3B shows a transmission signal when two channels are used at the same time. The center frequency of the transmission signal is fc and the frequency band is 4Δf.
Is. FIG. 3C shows a transmission signal when three channels are used at the same time. The center frequency of the transmission signal is fc and the frequency band is 6Δf.

First, in step S11 of FIG. 2, the control unit 70a of the transmission device matches the frequency band occupied by the control signal to be transmitted with the transmission signal (first IF) generated by the digital signal modulator 11a. Signal) and the local oscillation frequency of the first local oscillator 24a. Also, make sure that the center frequency of the control signal that contains the control information for notifying the other party of information necessary for wireless communication such as the transmission time of itself and the frequency band of the transmission signal matches the center frequency of the frequency band used for transmission. In addition, the local oscillation frequency of the second local oscillator 34 is also adjusted. In step S12, the transmission device generates a control signal and actually performs transmission.

In step S13, the control unit 70 of the transmission device
a adjusts the frequency band of the transmission signal (first IF signal) generated by the digital signal modulator 11a based on the frequency band of the data signal to be transmitted by itself, The upper edge of the upper limit frequency of the first IF bandpass filter 14 (f for a signal of one channel is f
Adjust so that it comes to c + 2Δf).

In step S14, the first local oscillator 2
The local oscillation frequency of 4a is adjusted so that the lower limit frequency of the second IF signal is the lower edge of the second IF bandpass filter 25 (fc-2Δf in the case of a signal of one channel).
Make adjustments to come to. Further, the local oscillation frequency of the second local oscillator 34 is adjusted so that the center frequency of the RF signal obtained by up-converting the second IF signal matches the frequency band of the channel used for transmission.

In step S15, the data signal is actually generated and transmitted, and if the transmission process is to be continued, the process returns to step S11, and if not, the transmission process is ended (step S16).

Next, the correlation between the filter and the transmission signal will be described with reference to FIG. FIG. 4 shows the case where there are three frequency bands of the transmission signal, and the first I
The F band pass filter 14 has the characteristics of the center frequency fc1 and the pass frequency band 6Δf, and the second band pass filter 25 has the characteristics of the center frequency fc2 and the pass frequency band 6Δf. The pass frequency band of the band pass filters 14 and 25 is set according to the transmission signal having the maximum frequency band. In other words, the pass frequency band of each band pass filter is (maximum number of simultaneously transmittable channels × 2Δf).

FIG. 4A1 is a correlation diagram relating to the first IF signal when one channel is used for the transmission signal. Reference numeral 81-1 indicates the frequency characteristic of the first IF signal, reference numeral 91. Indicates the frequency characteristics of the first IF bandpass filter 14. (A2) of FIG. 4 is a correlation diagram regarding the second IF signal when one channel is used for the transmission signal, reference numeral 81-2 indicates the frequency characteristic of the second IF signal, and reference numeral 92 indicates the second. The frequency characteristics of the IF band pass filter 25 of FIG.

FIG. 4 (b1) is a correlation diagram regarding the first IF signal when two channels are used for the transmission signal, and reference numeral 82-1 indicates the frequency characteristic of the first IF transmission signal. . FIG. 4B2 is a correlation diagram regarding the second IF signal when two channels are simultaneously used for the transmission signal, and the reference numeral 82-2 indicates the frequency characteristic of the second IF signal.

FIG. 4C1 is a correlation diagram regarding the first IF signal when three channels are simultaneously used for the transmission signal, and reference numeral 83-1 indicates the frequency characteristic of the first IF signal. . FIG. 4C2 is a correlation diagram regarding the second IF signal when three channels are simultaneously used for the transmission signal, and reference numeral 83-2 indicates the frequency characteristic of the second IF transmission signal.

The frequency band of one channel is 20 MHz,
Carrier center frequency (RF) of RF signal is 25.00G
Hz, carrier center frequency of the second IF signal (fc2)
Is 2440 MHz, and the carrier center frequency (fc1) of the first IF signal is 40 MHz. The pass frequency bandwidths of the first IF band pass filter 14 and the second band pass filter 25 have characteristics that match the signal frequency bandwidth of the maximum channel (in this case, 3 channels). In the example of the first embodiment, the pass frequency band of the first IF bandpass filter 14 is 10 MHz to 70 M.
Hz, and the pass frequency band of the second IF bandpass filter 25 is 2410 MHz to 2470 MHz.

When the transmission signal uses only one channel, the center frequency I of the transmission signal in the first IF frequency band
For F1, 2Δf may be added to fc1. IF1 = fc1 + 2Δf = 40 + 2 × 10 = 60 (MHz) (Equation 1-1) That is, the signal modulator 11a may generate a transmission signal having a center frequency of 60 MHz and a frequency band of 20 MHz (see (a1) in FIG. 4).

Next, in order to up-convert the transmission signal of the first IF frequency band to the second IF frequency band, the center frequency IF2 of the transmission signal of the second IF frequency band is f
Since it is sufficient to subtract 2Δf from c2, IF2 = fc2-2Δf = 2440-2 × 10 = 2420 (MHz) (Equation 1-2). That is, the local frequency LO1 emitted from the first local oscillator 24a is LO1 = IF2-IF1 = 2420-60 = 2360 (MHz) (Equation 1-3) (see (a2) in FIG. 4).

Further, the second IF signal is fed with a center frequency of 25G.
In order to up-convert to the RF signal of Hz, the second
The local frequency LO2 emitted by the local oscillator 34 is LO2 = RF-IF2 = 25-2.42 = 22.58 GHz (Equation 1-4).

When the transmission signal uses two channels at the same time, the center frequency IF1 of the transmission signal in the first IF frequency band can be obtained by adding Δf to fc1. Becomes That is, it suffices to generate a transmission signal having a center frequency of 50 MHz and a frequency band of 40 MHz in the signal modulator 11a (see (b1) in FIG. 4).

Next, in order to up-convert the transmission signal of the first IF frequency band to the second IF frequency band, the center frequency IF2 of the transmission signal of the second IF frequency band is f
Since it is sufficient to subtract Δf from c2, IF2 = fc2-Δf = 2440-10 = 2430 (MHz) (Equation 2-2). That is, the local frequency LO1 generated by the first local oscillator 24 is LO1 = IF2-IF1 = 2430-50 = 2380 (MHz) (Equation 2-3) (see (b2) in FIG. 4).

Further, the second IF signal has a center frequency of 25G.
In order to up-convert to the RF signal of Hz, the second
The local frequency LO2 emitted by the local oscillator 34 is LO2 = RF-IF2 = 25-2.43 = 22.57 GHz (Equation 2-4).

When the transmission signal uses three channels at the same time, the center frequency IF1 of the transmission signal in the first IF frequency band may remain fc1. Becomes

That is, it suffices to generate a transmission signal having a center frequency of 40 MHz and a frequency band of 60 MHz in the signal modulator 11a (see (c1) in FIG. 4). Then the first IF
In order to up-convert the transmission signal of the frequency band to the second IF frequency band, the center frequency IF2 of the transmission signal of the second IF frequency band may be fc2 as it is. Becomes

That is, the local frequency LO1 generated by the first local oscillator 24a is LO1 = IF2-IF1 = 2440-40 = 2400 (MHz) (Equation 3-3) (see (c2) in FIG. 4). ).

Further, the second IF signal has a center frequency of 25G.
In order to up-convert to the RF signal of Hz, the second
The local frequency LO2 emitted from the local oscillator 34 is: LO2 = RF-IF2 = 25-2.44 = 22.56 GHz (Equation 3-4).

<Second Embodiment> The second embodiment will be described below. FIG. 5 is a block diagram showing the configuration of the transmitting apparatus according to the second embodiment. The main difference from the first embodiment is that the baseband transmitter 2
At 0b, the baseband signal is directly fed to the second I
This is a point that the F transmission signal is up-converted, and the specifications of the signal modulation unit 10b and the control unit 70b are partially different accordingly. Other, second IF transmission unit 30, R
The F transmitter 40 and the transmitting / receiving antenna 50 have the same configurations and functions as those of the example of the first embodiment.

The digital signal modulator 11b having a transmission signal generating means generates a baseband signal based on the information on the frequency band of the transmission signal transmitted by the control unit 70b. An unnecessary harmonic component such as a second harmonic wave or a third harmonic wave is removed from the baseband signal by the digital filter 12b having a low-pass filter function, and the D / A converter 13b.
Is converted from a digital signal to an analog signal.

Next, the analogized baseband signal passes through the baseband low-pass filter 15, and the baseband transmission amplifier 26 first frequency converter 23b.
Amplified to a signal power suitable for input. The baseband signal is up-converted to a second IF signal by the local signal input from the first local oscillator 24b in the first frequency converter 23b.

The transmission signal processing and control method from the transmission / transmission antenna 50 to the transmission / transmission antenna 50 after being up-converted to the second IF signal are as described in the example of the first embodiment. Further, the transmission operation flow of the transmission device of the example of the second embodiment is the same as that of the first embodiment shown in FIG.

FIG. 6 is a diagram showing an example of the correlation between the filter and the transmission signal according to the second embodiment of the present invention on the frequency axis. FIG. 6 shows the case where there are three transmission frequency bands, and the baseband low-pass filter 15
Has a characteristic of a maximum pass frequency 3Δf, and the second IF bandpass filter 25 has a characteristic of a center frequency fc2 and a maximum pass frequency band 6Δf.

FIG. 6 (a2) is a correlation diagram regarding a signal when one channel is used for the transmission signal, and is the same as (a2) of FIG. 4 described above. (A3) of FIG. 6 is a correlation diagram regarding the baseband signal when one channel is used for the transmission signal, reference numeral 81-3 indicates the frequency characteristic of the baseband signal, and reference numeral 93 indicates the baseband low-pass filter 15. The frequency characteristic is shown, and the reference numeral 94 shows the folding frequency characteristic of the baseband low-pass filter 15.

FIG. 6 (b2) is a correlation diagram concerning signals when two channels are simultaneously used for transmission signals,
This is the same as (b2) in FIG. (B3) of FIG.
Is a correlation diagram regarding a baseband signal when two channels are simultaneously used for a transmission signal, and reference numeral 82-3 indicates the frequency characteristic of the baseband signal.

FIG. 6 (c2) is a correlation diagram concerning signals when three channels are simultaneously used for transmission signals,
This is the same as (c2) in FIG. (C3) of FIG.
Is a correlation diagram regarding a baseband signal when three channels are simultaneously used for a transmission signal, and reference numeral 83-3 indicates a frequency characteristic of the baseband signal.

A specific example of the transmitting apparatus according to the second embodiment will be described with reference to FIG. The frequency band of one channel is 20 MHz, the center frequency (RF) of the carrier center of the RF signal is 25.00 GHz, and the second IF
The carrier center frequency (fc2) of the frequency band signal is 24
It is 40 MHz. Baseband low-pass filter 15
And the pass frequency band of the second IF band pass filter 25 has a characteristic that matches the transmission signal band at the time of the maximum channel (in this case, at the time of three channels). In the example of the second embodiment, the pass frequency band of the baseband low-pass filter 15 is 30 MHz or less (-30 MHz to +30 MHz including the signal folding frequency),
The pass frequency band of the second IF bandpass filter 25 is 2410 MHz to 2470 MHz.

When the transmission signal uses only one channel, the center frequency BB of the transmission signal in the baseband frequency band may be 2 Hz added to 0 Hz. Becomes That is, the signal generator 11b may generate a transmission signal having a center frequency of 20 MHz and a frequency band of 20 MHz (see (a3) in FIG. 6).

Next, in order to up-convert the transmission signal of the baseband frequency band to the second IF frequency band,
The center frequency IF2 of the transmission signal in the second IF frequency band is
Since it is sufficient to subtract 2Δf from fc2, IF2 = fc2-2Δf = 2440-2 × 10 = 2420 (MHz) (Equation 1-6). That is, the local frequency LO1 generated by the first local oscillator 24b is: LO1 = IF1-BB = 2420-20 = 2400 (MHz) (Equation 1-7) (see (a2) in FIG. 6).

Further, the second IF signal has a center frequency of 25G.
In order to up-convert to the RF signal of Hz, the second
The local frequency LO2 emitted from the local oscillator 34 is: LO2 = RF-IF2 = 25-2.40 = 22.60 GHz (Equation 1-8).

When the transmission signal uses two channels at the same time, the center frequency BB of the transmission signal in the baseband frequency band may be 0 Hz plus Δf. Becomes That is, it suffices to generate a transmission signal having a central frequency of 10 MHz and a frequency band of 40 MHz in the signal modulator 11b (see (b3) in FIG. 6).

Next, in order to up-convert the transmission signal in the base band frequency band to the second IF frequency band,
The center frequency IF2 of the transmission signal in the second IF frequency band is
Since it is sufficient to subtract Δf from fc2, IF2 = fc2-Δf = 2440-10 = 2430 (MHz) (Equation 2-6). That is, the local frequency LO1 generated by the first local oscillator 24b is LO1 = IF2-BB = 2430-10 = 2420 (MHz) (Equation 2-7) (see (b2) in FIG. 6).

Further, the second IF signal has a center frequency of 25G.
In order to up-convert to the RF signal of Hz, the second
The local frequency LO2 emitted by the local oscillator 34 is: LO2 = RF-IF2 = 25-2.42 = 22.58 GHz (Equation 2-8).

When the transmission signal uses three channels at the same time, the center frequency BB of the transmission signal in the baseband frequency band may remain 0 Hz. Becomes That is, the center frequency is 0 Hz and the frequency band is 60.
The transmission signal of MHz may be generated by the signal generation 11b (see (c3) in FIG. 6).

Next, in order to up-convert the transmission signal in the baseband frequency band to the second IF frequency band,
The center frequency IF2 of the transmission signal in the second IF frequency band is
As it is fc2 as it is, Becomes That is, the local frequency LO1 generated by the first local oscillator 24b is LO1 = IF2-BB = 2440-0 = 2440 (MHz) (Equation 3-7) (see (c2) in FIG. 6).

Further, the second IF signal is fed with a center frequency of 25G.
In order to up-convert to the RF signal of Hz,
The local frequency LO2 emitted by the local oscillator 24b is: LO2 = RF-IF2 = 25-2.44 = 22.56 GHz (Equation 3-8).

As described above, by providing the wireless communication device with the transmitting device according to the first or second embodiment described above, the wireless communication system using signals in a plurality of frequency bands is used for transmission. It becomes possible to transmit a wireless signal. For example, the wireless communication device of the present invention can be used as a wireless communication terminal of the low power wireless communication system in the 25 GHz band described in the section of the related art.

[0081]

According to the transmitting apparatus of the present invention, the number of filters for removing harmonic components and noise components generated at the stage of generating a transmission signal is not increased for transmitting signals in different frequency bands. Moreover, it is possible to transmit a plurality of radio signals in different frequency bands without providing a switch circuit for switching the filters. As a result, the number of parts can be reduced, which is effective in reducing the manufacturing cost and downsizing the transmitter.

Further, unnecessary harmonic components such as the second harmonic wave and the third harmonic wave can be removed by a digital filter having a bandpass filter or a lowpass filter function. Even when the digital filter is not used, the effect of the invention is obtained, and in that case, further cost advantage can be expected.

Further, in a wireless communication system using signals in a plurality of frequency bands, the transmitter of the present invention is provided in the wireless communication device to transmit signals in all frequency bands used in the wireless communication system. Will be possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of a transmission device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a flowchart regarding a transmission method of a transmission apparatus according to the first embodiment and the second embodiment of the present invention.

FIG. 3 is a diagram showing, on a frequency axis, an example of frequency characteristics of a transmission signal according to the first and second embodiments of the present invention.

FIG. 4 is a diagram showing an example of a correlation between a filter and a transmission signal according to the first embodiment of the present invention on a frequency axis.

FIG. 5 is a block diagram showing a configuration example of a transmission device according to a second embodiment of the present invention.

FIG. 6 is a diagram showing, on a frequency axis, an example of a correlation between a filter and a transmission signal according to a second embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration example of a conventional transmission device.

[Explanation of symbols]

10a, 10b, 10c Signal modulators 11a, 11b, 11c Digital signal modulators 12a, 12b, 12c Digital filters 13a, 13b, 13c D / A converters 14, 121-1, 122-2, 123-n First I
F band pass filter 15 Base band low pass filter 20a, 120 First IF transmission unit 20b Base band transmission unit 22, 122 First IF transmission amplifier 23a, 23b, 123 First frequency converter 24a, 24b, 124 First Local oscillator 26 Baseband transmission amplifier 30, 130 Second IF transmission unit 31, 131-1, 132-2, 133-n Second I
F band pass filter 32,132 2nd IF transmission amplifier 33,133 2nd frequency converter 34,134 2nd local oscillator 35,135 RF band pass filter 40 RF transmission part 42 RF power amplifier 43 Transmission / reception switch 50 Transmission / reception antennas 70a, 70b, 170 Control units 81-1, 81-2, 81-3 Transmission signal frequency characteristics during 1-channel transmission 82-1, 82-2, 82-3 Transmission signal frequency during 2-channel simultaneous transmission Characteristics 83-1, 83-2, 83-3 Transmission signal frequency characteristics at the time of simultaneous three-channel transmission 91 Frequency characteristics of the first IF bandpass filter 92 Frequency characteristics of the second IF bandpass filter 93 Baseband lowpass filter Frequency characteristics 94 Baseband low-pass filter folding frequency characteristics 127, 129 First IF Switch 137, 139 the second IF switch

Claims (13)

[Claims] 1. A modulator for modulating an input signal into a first intermediate frequency signal in a predetermined frequency band, an IF converter for converting the first intermediate frequency signal into a high frequency signal, and transmitting the high frequency signal. A transmitting device comprising an RF transmitting unit and a control unit for controlling each unit, wherein the modulating unit passes a signal modulating unit for modulating the first intermediate frequency signal and the first intermediate frequency signal. And a frequency of the modulation unit so that the edge of the frequency band of the first intermediate frequency signal is aligned with the edge of the pass frequency band of the first IF filter. A transmission device characterized by adjusting and setting. 2. The IF conversion unit converts the first intermediate frequency signal modulated by the modulation unit into a second intermediate frequency signal, and a first frequency conversion unit, and the second intermediate frequency signal. A first IF converter having a second IF filter that passes the second IF filter, and a second IF converter that converts the second intermediate frequency signal into a high frequency signal
And a second IF conversion unit having frequency conversion means, wherein the control unit aligns an edge of a frequency band of the first intermediate frequency signal with an edge of a pass frequency band of the first IF filter. The frequency of the modulation section is adjusted and set, and the frequency of the first frequency conversion means is adjusted so that the edge of the frequency band of the second intermediate frequency signal is aligned with the edge of the pass frequency band of the second filter. The transmitter according to claim 1, wherein the transmitter is set. 3. The modulator includes a digital filter for removing unnecessary harmonic components of the intermediate frequency signal, and a D / A converter for converting a signal passed through the digital filter into an analog signal. 3. The control unit adjusts and sets the frequency of the modulation unit so that the edge of the frequency band of the first intermediate frequency signal is aligned with the edge of the pass frequency band of the digital filter. The transmission device according to 1. 4. The transmission apparatus according to claim 1, wherein the first IF filter is a bandpass filter or a lowpass filter. 5. The transmitter according to claim 3, wherein the digital filter is a digital filter having a function of a bandpass filter or a lowpass filter. 6. The transmission device according to claim 2, wherein the second IF filter is a bandpass filter or a highpass filter. 7. A modulator for modulating an input signal into a baseband signal in a predetermined frequency band, and an IF for converting the baseband signal via an intermediate frequency or into a high frequency signal.
A transmitter comprising: a converter, an RF transmitter for transmitting the high-frequency signal, and a controller for controlling each unit, wherein the modulator includes a signal modulator for modulating the baseband signal; And a control unit that adjusts the frequency of the modulation unit so that the edge of the frequency band of the baseband signal is aligned with the edge of the pass frequency band of the baseband filter. A transmitting device characterized by: 8. The IF conversion section includes first frequency conversion means for converting the baseband signal modulated by the modulation section into an intermediate frequency signal, and an IF filter for passing the intermediate frequency signal. 1 IF conversion unit and a second IF conversion unit including a second frequency conversion unit that converts the intermediate frequency signal into a high frequency signal, wherein the control unit controls the pass frequency band of the baseband filter. The frequency of the modulator is adjusted and set so that the edges of the frequency band of the baseband signal are aligned with the edges, and the edges of the frequency band of the intermediate frequency signal are aligned with the edges of the pass frequency band of the IF filter. 8. The transmitter according to claim 7, wherein the frequency of the first frequency conversion means is adjusted and set. 9. The modulator includes a digital filter for removing unnecessary harmonic components of the baseband signal,
D / A conversion means for converting the pass signal of the digital filter into an analog signal, wherein the control unit aligns the edge of the frequency band of the baseband signal with the edge of the pass frequency band of the digital filter. 9. The transmitter according to claim 7, wherein the frequency of the modulator is adjusted and set. 10. The baseband filter is a low-pass filter, wherein the baseband filter is a low-pass filter.
The transmission device according to 1. 11. The transmission device according to claim 9, wherein the digital filter is a digital filter having a low-pass filter function. 12. The transmitter according to claim 7, wherein the IF filter is a bandpass filter or a highpass filter. 13. A wireless communication device comprising the transmitting device according to claim 1. Description: