JPH11274947A - Radio transmitter, and radio transmission unit used for the radio transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adequately ensure variable range of a transmission output level, while suppressing the deterioration in the frequency characteristic. SOLUTION: An intermediate frequency variable amplifier 1 amplifies transmission signal at an optional gain and gives the amplified signal to a radio transmission unit 21. In the radio transmission unit, a local signal variable amplifier 23 amplifies a local signal generated from an oscillator 2 at an optional gain, and a mixer 4 combines the amplified signal with the transmission signal to convert the frequency band of the transmission signal into a radio frequency band. A 1st BPF5 and a 2nd BPF7 eliminate an unwanted component of the transmission signal with the converted radio frequency band and a driver amplifier 6 and a power amplifier 8 amplify the resulting signal at a fixed gain. In this case, a control circuit 22 respectively controls the gain of the intermediate frequency variable amplifier 1 and the local signal variable amplifier 23 so as to adjust the transmission output level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio transmitter having a function of adjusting a transmission output level and a radio transmission unit used in the radio transmitter.

[0002]

2. Description of the Related Art CDMA (Code Division Multiple Acc)
ess) In the radio equipment used in the system, it is necessary to adjust the transmission output level. FIG. 4 is a block diagram showing a configuration of a conventional wireless transmitter having a function of adjusting a transmission output level.

The radio transmitter shown in FIG. 1 includes an intermediate frequency variable amplifier 1, an oscillator 2, a local amplifier 3, a mixer 4, a first band-pass filter (first BPF) 5, a driver amplifier 6, and a second band-pass filter. (2nd BPF)
7, a power amplifier 8 and a control circuit 9. The transmission output level is adjusted by changing the gain of the intermediate frequency variable amplifier 1 under the control of the control circuit 9 and adjusting the level of the input intermediate frequency signal.

However, a CDMA system generally requires a variable output level range of 80 dB. It is difficult to stably secure such a variable range with one amplifier, and there is a possibility that a signal may be buried in noise in the middle of a circuit in a current component C / N. I will be cut off.

As a countermeasure, a radio transmitter having a configuration as shown in FIG. 5 has been considered. The wireless transmitter shown in FIG. 1 includes an intermediate frequency variable amplifier 1, an oscillator 2, a local amplifier 3, a mixer 4, a first BPF 5, a second BPF 7, a power amplifier 8, a variable driver amplifier 10, and a control circuit 1.
Consists of one. That is, a variable driver amplifier 10 and a control circuit 11 are provided instead of the driver amplifier 6 in the configuration shown in FIG. 4, and the gains of the intermediate frequency variable amplifier 1 and the variable driver amplifier 10 are changed under the control of the control circuit 11. Thus, the transmission output level is adjusted.

When the configuration shown in FIG. 5 is adopted, the variable driver amplifier 10 having the configuration shown in FIG. 6 is used. As shown in FIG. 1, the variable driver amplifier 10 includes a variable attenuator 10a, a first amplifier 10b, and a second amplifier 10c connected in series.

A first amplifier 10b and a second amplifier 10c
, The power is always supplied, and the gain is changed by changing the gain of the variable attenuator 10 a according to a gain control signal given from the control circuit 11.

Therefore, when the transmission output level is reduced, the transmission signal is attenuated by lowering the gain of the variable attenuator. At this time, however, the noise is smaller than the original attenuation of the transmission signal component. The amount of component attenuation is reduced. For this reason, as the gain is reduced, the transmission signal component is more likely to be buried in the noise component, and the NF (noise figure) deteriorates. The variable range also needs to be widened to 40 dB, and it is very difficult to configure an optimal matching circuit for the entire variable range. As a result, there is a problem that the frequency characteristic changes depending on the value of the transmission output level, and the control data required for the correction becomes enormous.

[0009]

As described above, conventionally,
When the transmission output level is adjusted by changing only the level of the input intermediate frequency signal, it is difficult to stably secure a sufficient variable range.

In order to adjust the transmission output level by changing both the level of the input intermediate frequency signal and the level of the signal in the radio frequency band after frequency conversion in order to secure a sufficient variable range, Depending on the value of the output level, the frequency characteristics change, resulting in a problem that the control data required for the correction becomes enormous.

The present invention has been made in view of such circumstances, and it is an object of the present invention to sufficiently secure a variable range of a transmission output level while suppressing deterioration of frequency characteristics. An object of the present invention is to provide a wireless transmitter and a wireless transmission unit used in the wireless transmitter.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, a first aspect of the present invention provides a radio transmitter for amplifying a transmission signal with a gain designated from the outside, such as a variable amplifier for an intermediate frequency. Amplifying means, local signal generating means such as an oscillator for generating a local signal of a predetermined frequency, and a local variable amplifier for amplifying a local signal generated by the local signal generating means with a gain designated from the outside And the like, and by mixing the local signal after being amplified by the local signal amplifying means with the transmitting signal after being amplified by the transmitting signal amplifying means, the frequency of the transmitting signal can be set to a predetermined radio frequency. Frequency conversion means such as a mixer for converting the frequency into a frequency band, and after the frequency conversion by the frequency conversion means Amplifies the transmission signal at a predetermined fixed gain, for example, the first band-pass filter, driver amplifier,
A radio frequency signal amplifying means comprising a second band-pass filter and a power amplifier; and a gain control means such as a control circuit. The gain control means allows a transmission signal amplified by the radio frequency signal amplifying means to be transmitted. The respective gains of the transmission signal amplifying means and the local signal amplifying means are controlled to be at a predetermined level.

By taking such means, the transmission signal amplified by the transmission signal amplifying means at an arbitrary gain and the local signal amplified by the local signal amplifying means at the arbitrary gain are transmitted to the frequency conversion means. The transmission signal is frequency-converted into a radio frequency band by being combined, and then amplified with a fixed gain by a radio frequency signal amplifying means. The transmission output level is adjusted by changing the gain of the transmission signal amplifier and the gain of the local signal amplifier under the control of the gain controller.

In order to achieve the above object, a second aspect of the present invention is a radio transmitter, comprising: a transmission signal amplifying means such as an intermediate frequency variable amplifier for amplifying a transmission signal with an externally designated gain; Local signal generating means such as an oscillator for generating a local signal having a frequency, and local signal amplifying means such as a local variable amplifier for amplifying a local signal generated by the local signal generating means with a gain specified from the outside And the local signal amplified by the local signal amplifying means is mixed with the transmission signal amplified by the transmission signal amplifying means to convert the frequency of the transmission signal into a predetermined radio frequency band. For example, a frequency conversion unit such as a mixer and a transmission signal after frequency conversion by the frequency conversion unit are excluded. And a radio frequency signal amplifying unit including, for example, a first bandpass filter, a variable driver amplifier, a second bandpass filter, and a power amplifier, and a gain control unit such as a control circuit. The gain control means controls the respective gains of the transmission signal amplifying means, the local signal amplifying means, and the radio frequency signal amplifying means so that the transmission signal after being amplified by the radio frequency signal amplifying means has a predetermined level. I did it.

By taking such means, the transmission signal amplified by the transmission signal amplifying means at an arbitrary gain and the local signal amplified by the local signal amplifying means at the arbitrary gain are transmitted to the frequency conversion means. After the transmission signal is frequency-converted into a radio frequency band by being combined, the signal is amplified with an arbitrary gain by a radio frequency signal amplifying means. The transmission output level is adjusted by changing the gain of the transmission signal amplifier, the gain of the local signal amplifier, and the gain of the radio frequency signal amplifier under the control of the gain controller.

According to a third aspect of the present invention, there is provided a radio transmitting unit for amplifying a local signal supplied from the outside with a gain designated from the outside, such as a local signal amplifier such as a local variable amplifier. Means for mixing a local signal after being amplified by the local signal amplifying means with a transmission signal given from the outside, thereby converting the frequency band of the transmission signal into a predetermined radio frequency band. Conversion means.

By taking such means, a local signal whose level has been adjusted by amplifying the gain with an arbitrary gain according to the designation from the outside is synthesized with the transmission signal,
Since the frequency band of the transmission signal can be frequency-converted into a radio frequency band, by using this radio communication unit as the local signal amplifying unit and the frequency conversion unit in the two inventions, the radio transmission unit as in the two inventions can be used. Machine can be easily realized.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing a configuration of a wireless transmitter according to a first embodiment of the present invention. FIG.
The same reference numerals are given to the same parts as.

As shown in FIG. 1, the wireless communication apparatus according to the present embodiment includes an intermediate frequency variable amplifier 1, an oscillator 2, a first band-pass filter (first BPF) 5, a driver amplifier 6,
A second bandpass filter (second BPF) 7, a power amplifier 8, a wireless transmission unit 21 and a control circuit 22 are provided.

An intermediate frequency variable amplifier 1, an oscillator 2, a radio transmission unit 21, a first BPF 5, a driver amplifier 6,
The second BPF 7 and the power amplifier 8 are connected in series in this order, and a transmission signal in an intermediate frequency band is input to the intermediate frequency variable amplifier 1 and an output of the power amplifier 8 is supplied to an antenna (not shown). It becomes a transmission signal in the frequency band.

The oscillator 2 is connected to a radio transmission unit 21. The wireless transmission unit 21 has a local variable amplifier 23 and a mixer 4.

The local variable amplifier 23 includes an oscillator 2
Output is given. The output of the local variable amplifier 23 is provided to the mixer 4. The output of the intermediate frequency variable amplifier 1 is separately provided to the mixer 4. Then, the output of the mixer 4 is given to the first BPF 5.

The control circuit 22 includes the intermediate frequency variable amplifier 1
And the gain of the local variable amplifier 23 is controlled to adjust the transmission output level. To operate this, the modulated intermediate frequency band transmission signal is input to the intermediate frequency variable amplifier 1. Then, the transmission signal is amplified by the intermediate frequency variable amplifier 1 at an arbitrary gain, and is then provided to the mixer 4 of the wireless transmission unit 21.

On the other hand, a local signal having a predetermined frequency is generated in the oscillator 2, and the local signal is input to the local variable amplifier 23 of the wireless transmission unit 21. Then, the local signal is amplified by the local variable amplifier 23 with an arbitrary gain, and is then provided to the mixer 4.

In the mixer 4, the transmission signal amplified by the intermediate frequency variable amplifier 1 is added to the local variable amplifier 2.
The local signals amplified in step 3 are combined. Thereby, the transmission signal is frequency-converted from the intermediate frequency band to the radio frequency band.

Unnecessary spurs are generated in the transmission signal after the frequency conversion in the frequency conversion, and this unnecessary spurious is removed by the first BPF 5. Thereafter, the transmission signal is amplified by the driver amplifier 6 with a constant gain, and unnecessary spurious generated at this time is removed by the second BPF. Then, the transmission signal is further amplified by a constant gain by a power amplifier, and then output to be supplied to, for example, an antenna.

At this time, the control circuit 22 obtains a desired transmission output level with the total gain of the intermediate frequency variable amplifier 1, local variable amplifier 23, mixer 4, driver amplifier 6 and power amplifier 8. The intermediate frequency variable amplifier 1 and the local variable amplifier 23 have a variable gain for the intermediate frequency within a range that does not deteriorate the NF (noise figure) or change the frequency characteristics in each of the intermediate frequency variable amplifier 1 and the local variable amplifier 23. The respective gains of the amplifier 1 and the local variable amplifier 23 are controlled.

As described above, according to the present embodiment, apart from changing the level of the transmission signal in the intermediate frequency band, the level of the local signal is changed by the local variable amplifier 23. The variable range of the transmission output level of the communication device as a whole can be largely secured by combining the variable range of the intermediate frequency variable amplifier 1 and the variable range of the local variable amplifier 23.

Moreover, in the present embodiment, the mixer 4 generally has both a transmission signal input and a local signal input of Hig.
Since the impedance is h, even if the signal level is varied in a wide range and the output impedance of the intermediate frequency variable amplifier 1 and the local variable amplifier 23 fluctuates, the frequency characteristics of the output signal hardly change.

Further, in general, the relationship between the local signal level and the output of the mixer 4 when the level of the transmission signal input is constant has characteristics as shown in FIG. That is, the change amount y of the output level of the mixer 4 with respect to the change of the fixed amount x of the local signal level is y> x
Relationship. From this, the amount of change in the local signal level for changing the transmission output level by a fixed amount may be smaller than the amount of change in the transmission output level, and the variable range of the local variable amplifier 23 can be kept small.

Further, the S / N ratio of the local signal is better than that of the transmission signal. Therefore, even when the gain of the local signal variable amplifier 23 is small, the NF hardly deteriorates. From these facts, it is possible to sufficiently and stably secure the variable range of the transmission output level while suppressing the deterioration of the frequency characteristics.

(Second Embodiment) FIG. 3 is a block diagram showing a configuration of a wireless communication device according to a second embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. The same parts as those in FIG. 5 are denoted by the same reference numerals.

As shown in this figure, the radio communication device according to the present embodiment comprises an intermediate frequency variable amplifier 1, an oscillator 2, a first BPF
5, a second BPF 7, a power amplifier 8, a variable driver amplifier 10, a wireless transmission unit 21, and a control circuit 24.

That is, the wireless transmitter according to the present embodiment has a variable driver amplifier 10 instead of the driver amplifier 6 and a control circuit 24 instead of the control circuit 22 in the wireless transmitter according to the first embodiment. It is.

The operation of the wireless transmitter according to this embodiment is substantially the same as the operation of the wireless transmitter according to the first embodiment. However, the control circuit 24 includes the intermediate frequency variable amplifier 1, the local variable amplifier 23, the mixer 4, the variable driver amplifier 10
NF in each of the intermediate frequency variable amplifier 1, the local variable amplifier 23, and the variable driver amplifier 10 so that the total gain of the power amplifier 8 is appropriate to obtain a desired transmission output level.
The gain of each of the intermediate frequency variable amplifier 1, the local variable amplifier 23, and the variable driver amplifier 10 is controlled within a range that does not cause deterioration of (noise figure) or change in frequency characteristics.

Thus, also according to the present embodiment, the first
The same effect as in the embodiment can be obtained. Further, according to the present embodiment, since the gains of the three amplifiers of the intermediate frequency variable amplifier 1, the local variable amplifier 23, and the variable driver amplifier 10 are changed, the amount of change in the gain of each amplifier can be reduced. The operation can be performed only in the more stable operation range.

Since the variable driver amplifier 10 can reduce the variable amount of the gain in this way, it is possible to avoid the NF (noise figure) from deteriorating and the frequency characteristics from changing. Note that the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0038]

According to the first aspect of the present invention, there is provided a radio signal transmitter for amplifying a transmission signal with a gain specified from the outside, a local signal generator for generating a local signal of a predetermined frequency, A local signal generated by the local signal generating means, a local signal amplifying means for amplifying with a gain designated from the outside, and a transmission signal amplified by the transmission signal amplifying means and amplified by the local signal amplifying means. Frequency conversion means for converting the frequency of the transmission signal into a predetermined radio frequency band by mixing the local signals thereafter, and amplifying the transmission signal after frequency conversion by the frequency conversion means with a predetermined fixed gain Radio frequency signal amplifying means, and gain control means, and the gain control means amplifies the radio frequency signal amplifying means. Transmission signal after being has to control the respective gains of the transmission signal amplifier means and said local signal amplifying means to a predetermined level.

The radio transmitter according to the second aspect of the present invention comprises: a transmission signal amplifying means for amplifying a transmission signal with a gain specified from the outside; a local signal generation means for generating a local signal of a predetermined frequency; A local signal amplifying means for amplifying the local signal generated by the signal generating means with a gain designated from the outside; and a transmission signal amplified by the transmission signal amplifying means and amplified by the local signal amplifying means. Frequency conversion means for converting the frequency of the transmission signal into a predetermined radio frequency band by mixing the local signal, and a transmission signal after frequency conversion by the frequency conversion means with a gain specified from the outside. Amplifying means for amplifying the radio frequency signal; and gain control means. Transmission signal after being amplified is to control the respective gains of the transmission signal amplifying means, said local signal amplifying means and the radio frequency signal amplifying means to a predetermined level by.

Thus, it is possible to provide a wireless transmitter capable of sufficiently securing the variable range of the transmission output level while suppressing the deterioration of the frequency characteristic. The wireless transmission unit according to the third aspect of the present invention includes a local signal amplifying means for amplifying a local signal supplied from the outside with a gain specified from the outside, and a local signal amplifying means for a transmission signal provided from the outside. Frequency mixing means for converting the frequency band of the transmission signal to a predetermined radio frequency band by mixing the local signals afterward, so that the transmission output level can be varied while suppressing the deterioration of the frequency characteristics. It is possible to provide a wireless communication unit capable of easily realizing the wireless transmitter as in the first and second inventions, which can sufficiently secure a range.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a relationship between a local signal level and an output of a mixer 4 when a transmission signal input level is assumed to be constant.

FIG. 3 is a block diagram showing a configuration of a wireless communication device according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional wireless transmitter having a function of adjusting a transmission output level.

FIG. 5 is a block diagram showing another configuration of a conventional wireless transmitter having a function of adjusting a transmission output level.

FIG. 6 is a diagram showing a configuration of a variable driver amplifier 10 in FIG. 5;

[Description of Signs] 1 ... Intermediate frequency variable amplifier 2 ... Oscillator 4 ... Mixer 5 ... First band pass filter (first BPF) 6 ... Driver amplifier 7 ... Second band pass filter (second BPF) 8 ... Power amplifier 21 ... Wireless transmission unit 22, 24 Control circuit 23 Local variable amplifier

Claims (3)

[Claims] 1. A transmission signal amplifying means for amplifying a transmission signal with a gain specified from the outside, a local signal generation means for generating a local signal of a predetermined frequency, and a local signal generated by the local signal generation means. Local signal amplifying means for amplifying with a gain designated from the outside, and by mixing the local signal after being amplified by the local signal amplifying means with the transmission signal after being amplified by the transmission signal amplifying means, Frequency conversion means for converting the frequency of the transmission signal into a predetermined radio frequency band; radio frequency signal amplification means for amplifying the transmission signal after frequency conversion by the frequency conversion means with a predetermined fixed gain; The transmission signal amplifying unit and the transmission signal amplifying unit so that the transmission signal after being amplified by the signal amplifying unit is at a predetermined level. Radio transmission apparatus being characterized in that includes a gain control means for controlling each gain of the local signal amplifying means. 2. A transmission signal amplifying means for amplifying a transmission signal with a gain designated from the outside, a local signal generation means for generating a local signal of a predetermined frequency, and a local signal generated by the local signal generation means. Local signal amplifying means for amplifying with a gain designated from the outside, and by mixing the local signal after being amplified by the local signal amplifying means with the transmission signal after being amplified by the transmission signal amplifying means, Frequency conversion means for converting the frequency of the transmission signal into a predetermined radio frequency band; radio frequency signal amplification means for amplifying the transmission signal after frequency conversion by the frequency conversion means with an externally designated gain; The transmission signal amplifying means so that the transmission signal after being amplified by the radio frequency signal amplifying means has a predetermined level.
A wireless transmission device comprising: a gain control unit that controls respective gains of the local signal amplification unit and the radio frequency signal amplification unit. 3. A local signal amplifying means for amplifying a local signal given from the outside with a gain designated from the outside, and a local signal amplified by the local signal amplifying means to a transmission signal given from the outside. And a frequency converter for frequency-converting the frequency band of the transmission signal into a predetermined radio frequency band.