JP2000013246A - Transmitter equipped with plural modulation systems - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce current consumption and to obtain wide transmit power variation width while suppressing distortion generated by a frequency converting means by providing a variable amplifying means in front of and behind the frequency converting means and setting operation conditions according to a selected modulation system and by variably controlling. SOLUTION: A control means 7 selects an arbitrary modulation system by which a modulated signal generating means 1 performs generation and variably controls the gains of 1st and 2nd variable amplifying means 2 and 4 according to the selected modulation system. Namely, the 1st and 2nd variable amplifying means 2 and 4 are both variably controlled for the standard which has wider transmit power variable amplification to obtain necessary variable width. Consequently, the input power range of the frequency converting means 3 is narrow and distortion suppression is easily designed. Further, a bias generating means 6 is controlled according to the selected modulation system so as to switch the operation state of a power amplifying means 5, thereby in case of a modulation system in which linearlity is not required, the current consumption is reducible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a configuration and a control method of a transmitter applicable to a communication system such as a portable telephone having a plurality of modulation schemes.

[0002]

2. Description of the Related Art A portable telephone will be described as an example of the prior art. Cellular phones have different modulation schemes and wireless transmission frequencies depending on the standards, and mobile phones that comply with each standard are required depending on the country / region where the service is used. If a plurality of standards can be used with one mobile phone, the convenience for the user will be greatly improved. For this reason, the development of shared machines conforming to two different standards has been promoted,
New standards are being developed that integrate different types of standards. For example, the IS-9 that has been put to practical use in the United States, Korea, and Hong Kong
The five standards are the latter, and radio frequencies conventionally assigned to analog modulation (FM) are shared with digital modulation (OQPSK). In digital modulation of this standard, CDMA (code division multiple access) is used as an access method, and since it has excellent confidentiality and anti-fading properties, it is attracting attention as a basic technology of next-generation mobile phones.

On the other hand, there is a GSM standard which is currently most widely used in the world, mainly in Europe. The use of digital modulation (GMSK), which has no amplitude component, allows the transmission power amplifier to be saturated and used, and the use of TDMA (time division multiple access) as the access method results in longer call and standby times. Is a possible standard. For example, if a mobile phone conforming to these two standards can be realized, it is very useful to reduce the necessity of changing the phone for each service area.

[0004] In addition to support for such a plurality of standards, the demand for smaller and lighter portable telephones is increasing year by year, and there is a demand for reducing the current consumption of circuits and downsizing of built-in batteries. . In order to realize a terminal conforming to a plurality of standards, a circuit scale is increased as compared with a terminal conforming to a single standard, and some measures are required to reduce current consumption.

FIG. 4 shows a configuration example of a transmitter used in the above-mentioned IS-95 standard. The modulation signal generating means 1 and 2 generate an FM modulation signal and an OQPSK modulation signal, respectively, and the control means controls to obtain either output. The selected modulation signal is amplified by the variable amplifying unit 1, converted to a desired transmission frequency by the frequency converting unit, and then transmitted through the fixed gain amplifying unit and the power amplifying unit. At this time, the control means controls the variable amplifying means 1 so that the transmission output power transmitted from the power amplifying means has a desired value, and controls the frequency converting means so that the transmission frequency transmitted from the power amplifying means has a desired value. Control.
In addition, when FM modulation with no amplitude component is selected, the power amplifying means is operated in saturation, and when OQPSK modulation is required to suppress amplitude distortion, the power consumption is controlled by controlling the bias generating means so that the power amplifying means operates linearly. Was reduced.

[0006]

In the prior art, it is possible to reduce the current consumption of the power amplifying means by the control described above. However, on the other hand, it is necessary to suppress the maximum output power of the variable amplifying means 1 in the preceding stage in order to suppress the distortion generated in the frequency converting means. This has to be provided, which causes an increase in current consumption in a stage preceding the power amplifying means.

As a solution to this problem, a configuration as shown in FIG. 5 can be considered. In this configuration, since the variable amplifying unit is provided at the subsequent stage of the frequency converting unit, the input power of the frequency converting unit 1 becomes constant, and it is easy to perform distortion suppression. However, the variable amplifying means 1 provided after the frequency converting means
However, since high-frequency operation is required, there arises a problem that the current consumption increases and the variable width becomes insufficient. GSM mentioned above
Considering the case of sharing with the standard, the variable control width of the transmission output power in the GSM standard is 28 dB (+5
dBm to +33 dBm) and 30 dB (0 dBm to +30 dBm) in the 1800 MHz band, and can be sufficiently realized even in the transmission frequency band.

[0008] However, the variable control width of the transmission output power required by the IS-95 standard is 20 dB (+8 dBm to +28 dBm) in the operation mode in analog modulation (FM), but is in digital modulation (OQPSK). 78dB (-48dBm to + 30dB) in the operation mode of
m) is required. For this reason, 900MHz
It is very difficult to realize a variable amplifying means for obtaining this variable width at the band transmission frequency.

[0009]

The object of the present invention is to provide variable amplifying means before and after the frequency converting means, to set the operating conditions of the power amplifying means in accordance with the selected modulation method, and to set the operating conditions of the selected modulation method. The problem is solved by variably controlling the gains of both variable gain means or variably controlling only one of them. For more information,
A modulation signal generating means having a function of generating at least two types of signals of different modulation schemes and a function of selecting and outputting any one type, and at least an arbitrary amplification of an output signal of the modulation signal generating means First variable gain means having a function of amplifying at a rate, frequency conversion means having a function of converting at least an output signal of the first variable gain means to a different frequency, and at least an output signal of the frequency conversion means The second variable gain means having the function of amplifying at the amplification factor of, the power amplifying means having the function of amplifying at least the output signal of the second variable gain means, and setting the operation state of at least the power amplifying means Bias generating means, and control means having a function of controlling the frequency conversion means so as to obtain at least a desired transmission frequency, wherein the control means An arbitrary modulation method to be generated by the modulation signal generating means is selected, and both or only one of the gains of the first variable gain means and the second variable gain means is variable according to the selected modulation method. And controlling the bias generating means for switching the operation state of the power amplifying means in accordance with the selected modulation method.

By performing the above control, in a transmitter having a plurality of modulation schemes and a plurality of variable transmission power widths,
It is possible to reduce current consumption and achieve a wide transmission power variable width while suppressing distortion generated by the frequency conversion means.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a system configuration diagram showing a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a modulation signal generating means having a function of generating signals of at least two or more different modulation schemes, and a function of selecting and outputting an arbitrary one kind, and 2 denotes at least a modulation signal generating means. First variable gain means having a function of amplifying an output signal at an arbitrary amplification factor, 3 is frequency conversion means having a function of converting an output signal of at least the first variable gain means to a different frequency, and 4 is at least frequency conversion. A second variable gain means having a function of amplifying an output signal of the means at an arbitrary gain.
Is a power amplifying means having a function of amplifying at least an output signal of the second variable gain means, 6 is a bias generating means for setting at least an operation state of the power amplifying means, and 7 is a frequency converting means for obtaining at least a desired transmission frequency. Control means having a function of controlling the The control means selects an arbitrary modulation method to be generated by the modulation signal generation means, and variably controls only one or both of the gains of the first variable gain means and the second variable gain means according to the selected modulation method. I do. That is, for a standard having a small transmission power variable width, only one of the first and second variable amplifying units is variably controlled, and the other is a fixed gain. For example, when the first variable amplifying means is fixed and the second variable amplifying means is variably controlled, the input power of the frequency converting means is constant and distortion suppression is easy, and the variable width required by the second variable amplifying means is sufficient. Can be obtained.

For a standard having a large transmission power variable width,
By variably controlling both the first and second variable amplification means, a required variable width can be obtained. Compared with the case where the required variable width is obtained only by the first variable amplifying means as in the conventional example shown in FIG. 4, there is an advantage that the input power range of the frequency converting means is narrower and the design of distortion suppression becomes easier. Further, by controlling the bias generation means to switch the operation state of the power amplification means according to the selected modulation method,
In a modulation method that does not require linearity, the power amplifying unit can be operated in saturation to reduce current consumption.

With the above configuration and control, in a transmitter having a plurality of modulation schemes and a plurality of variable transmission power ranges, reduction of current consumption and a wide range of variable transmission power can be realized if distortion generated by the frequency conversion means is suppressed. be able to. As described above, this embodiment is applicable not only to analog / digital shared mobile phones conforming to the IS-95 standard, but also to the GSM standard in Europe using GMSK modulation which has no amplitude component while being digital modulation. It is also effective for shared equipment with IS-95 standards. The variable control width of the transmission output power in the GSM standard is 28 dB (+5 dBm to +33 dBm) in the 900 MHz band, and 30 dB (0 dBm to +30 dBm) in the 1800 MHz band. When the variable amplifier has a variable gain, a sufficient power variable width can be obtained while suppressing distortion of the frequency converter. In addition, the current consumption can be reduced by saturating the power amplification means.

FIG. 2 is a system configuration diagram showing a second embodiment of the present invention. The mobile phone standard differs not only in the modulation method and the transmission power variable width but also in the transmission frequency and the transmission maximum power. Therefore, in order to realize a shared device conforming to a plurality of standards, it is desirable to have an amplifying unit suitable for each transmission frequency and maximum transmission power as a power amplifying unit. For this reason, in the present embodiment, the power amplifying unit of the first embodiment includes a plurality of amplifying units and has a function of selecting an arbitrary one to perform an amplifying operation. The control means controls to select an arbitrary number from among the plurality of amplifying means included in the power amplifying means according to the selected modulation method. For example, when one is selected, the respective amplifying means provided in the power amplifying means are those suitable for each standard. In the case of two or more, each amplifying means provided in the power amplifying means alone includes:
This is a case where a plurality of amplifying units are operated in parallel when a desired transmission output cannot be obtained. In this embodiment, in a transmitter having a plurality of modulation schemes and a plurality of variable transmission power ranges, it is possible to reduce current consumption and achieve a wide transmission power variable range while suppressing distortion generated by the frequency conversion means.

FIG. 3 is a system configuration diagram showing a third embodiment of the present invention. In the present embodiment, the power amplifying unit in the first embodiment includes at least an amplifying unit and a plurality of matching units connectable to the amplifying unit, and selects any one of the matching units to connect to the amplifying unit. It has a function. The control means controls to select an arbitrary number of matching means among a plurality of matching means included in the power amplification means according to the selected modulation scheme. In this embodiment, in a transmitter having a plurality of modulation schemes and a plurality of transmission power variable widths, it is possible to reduce current consumption and achieve a wide transmission power variable width while suppressing distortion generated by the frequency conversion means. Further, the power amplifying means of this embodiment has a plurality of matching circuits only as compared with the second embodiment, so that it can be made smaller.

Although the above embodiment has been described with reference to a portable telephone, it is obvious that the present invention is also effective when applied to wireless and wired communication systems having the same configuration.

[0018]

By performing the above-described control, in a transmitter having a plurality of modulation schemes and a plurality of variable transmission power ranges, it is possible to reduce current consumption and reduce a wide transmission power variable range while suppressing distortion generated by frequency conversion means. Can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a mobile phone according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a mobile phone according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a mobile phone according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a mobile phone illustrating an example of a conventional technique.

FIG. 5 is a configuration diagram of a mobile phone illustrating an example of a conventional technique.

[Explanation of symbols]

1, 11, 12, 13: modulated signal generating means, 2: first variable amplifying means, 3: frequency converting means, 4: second variable amplifying means, 5: power amplifying means, 6: bias generating means, 7
... control means, 8, 51, 52, 53, 54 ... amplifying means
55, 56 ... matching means.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K060 BB07 CC04 DD04 HH01 HH03 HH06 HH14 HH39 KK06 LL01 LL14

Claims (5)

[Claims] 1. Modulation signal generating means (1) having a function of generating signals of at least two or more different modulation schemes and a function of selecting and outputting any one type, and at least a function of generating the modulation signal. A first variable gain means (2) having a function of amplifying an output signal of the means (1) at an arbitrary gain, and a function of converting at least an output signal of the first variable gain means (2) to a different frequency; Frequency conversion means (3) having at least a second variable gain means (4) having a function of amplifying at least an output signal of the frequency conversion means (3) at an arbitrary gain. A power amplifying means (5) having a function of amplifying an output signal of the means (4); a bias generating means (6) for setting at least an operation state of the power amplifying means (5); and obtaining at least a desired transmission frequency. Control means (7) having a function of controlling the frequency conversion means (3), wherein the control means (7) selects an arbitrary modulation method generated by the modulation signal generation means (1). In addition, according to the selected modulation method, both or only one of the gains of the first variable gain means (2) and the second variable gain means (4) is variably controlled, and the selected modulation method is further changed. A transmitter having a plurality of modulation schemes, characterized in that the bias generation means (6) is controlled so as to switch the operation state of the power amplification means (5) in response. 2. A transmitter according to claim 1, wherein said power amplifying means (5) comprises at least a plurality of amplifying means (52, 52).
53) and a function of selecting an arbitrary one to perform an amplifying operation, and the amplification provided by the power amplifying means (5) according to the modulation method selected by the control means (7). A transmitter having a plurality of modulation schemes, characterized by controlling to select the means (52, 53). 3. The transmitter according to claim 1, wherein said power amplifying means comprises at least an amplifying means and a plurality of matching means connectable to said amplifying means.
6) and a function of selecting any one of the matching means (55, 56) and connecting to the amplifying means (54), and the modulation method selected by the control means (7). A transmitter having a plurality of modulation schemes, wherein the transmitter is controlled so as to select the matching means (55, 56) included in the power amplifying means (5) according to the following. 4. A transmitter provided in an arbitrary communication device, wherein the transmitter has at least the configuration and control method according to claims 1 to 3 and has a plurality of modulation schemes. 5. A transmitter equipped with a plurality of modulation schemes, wherein the transmitter has a configuration and a control method according to any one of claims 1 to 3. .