• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Methods and apparatus are described for transmitting signals from a single device in multiple radio frequency bands. The apparatus includes a transmitter 128 that transmits an RF communication signal. The transmitter consists of a power amplifier 200 that amplifies an RF communication signal in a first RF band or a second RF band. The transmitter has a composite transformer 202 that partially converts the impedance of the RF communication signal in the first RF band and completely converts the impedance of the RF communication signal into the characteristic impedance in the second RF band. The transmitter also includes a first path 204 for transmitting the RF communication signal in the first RF band and a second path 206 for transmitting the RF communication signal in the second RF band. The first path completes the impedance conversion of the RF communication signal when the system is operating in the first RF band, and the second path operates with characteristic impedance when the system is operating in the second RF band.
    公开号:KR20030010726A
    申请号:KR1020027017116
    申请日:2001-06-13
    公开日:2003-02-05
    发明作者:피터 난니；리 시앙；에릭 미드록
    申请人:모토로라 인코포레이티드；
    IPC主号:
    专利说明:

    METHOD AND APPARATUS FOR MULTIPLE BAND TRANSMISSION}
    [2] Multiple communication standards are required for wireless communication devices such as cellular and personal computer service (PCS) cordless phones that are compatible with many standards. With multi-mode functionality, a device can work with more than one system or standard, and depending on the standards available, users can potentially use the device on more than one continent or in more than one country. Multi-mode communication devices are designed to transmit and receive RF communication signals of digital or analog characteristics or combinations thereof, depending on the communication system operating at the user's topographical location. Standards for transmitting analog RF communication signals are typically advanced mobile phone systems (AMPS), and transmission standards for digital RF signals are time division multiple access (TDMA), code division multiple access (CDMA), and global system for GSM. may be selected from a number of multiple access technologies including mobile communication. Multi-mode devices include the electronic components needed to operate within these multiple standards, for example dual mode devices have the ability to operate in two systems that conform to two different standards. This allows a user to move from one system to another, the device being operated as long as it includes one of the standards of the system in which the multi-mode communication device operates. The transmitter of a multimode communication device is single mode or similar to a device designed to transmit within one frequency band, but is adapted to transmit in multiple frequency bands according to any of the analog or digital standard protocols described above.
    [3] Typical single band RF transmitter circuits include power amplifiers (PAs), band pass filters, impedance matching circuits, and antennas. The PA amplifies the communication signal according to the desired communication protocol. Impedance matching circuitry minimizes RF losses when passing signals from the PA to the antenna. The filter allows RF communication signals in the desired frequency band to be transmitted through the antenna to the air interface. Band pass filters and impedance matching circuits are generally specifically designed to operate in a given frequency band. Additional components are required to allow frequency band regulation to transmit in multiple adjacent or separate bands.
    [4] One way to achieve the multiband transmission function is to use two or more separate PA devices for the wireless communication device. This requires one PA for each mode or frequency band in which the device is designed to operate. It also requires providing a corresponding number of electrical paths, one for each PA and related circuitry for filtering and impedance matching. In such a scenario, the first PA and associated circuitry are optimized to operate in the first frequency band according to any of the analog or digital standards. The second PA and associated circuitry are optimized to operate in the second frequency band in accordance with the desired standard. This approach requires minimal design effort, but the PA is complex and expensive, requiring additional costs in manufacturing. In addition, cost and complexity are further exacerbated by the PA used for digital RF transmission.
    [5] The second way to achieve multiband transmission is to use a pin diode circuit. With a pin diode circuit, a single PA is followed by a pin diode switching network inserted into the input and output impedance matching network. The pin diode switching network controls the post amplifier impedance matching of the communication signal in response to the electrical command signal delivered by the microprocessor. Changing the impedance characteristics of the pin diode switching network also changes the frequency response of the circuit depending on the mode of operation of the device. For example, when the communication device is in the first communication mode, the pin diode switching network is switched to the corresponding first RF band. However, this method requires a large number of components, which increases both the cost and complexity of the circuit, making optimization and tuning very difficult. In addition, because the pin diodes are nonlinear, these circuits tend to distort desired communication signals and generate adjacent channel power (ACP) noise to interfere with users of nearby channels. This prevents it from being used in linear modulation schemes (CDMA and TDMA).
    [6] The third method uses a diplexing circuit following a single PA providing a first path and a second path, which are paths for each mode of the dual mode communication device. The first path is designed for the first RF band according to the first mode, and the second path is designed for the second RF band according to the second mode. In this configuration, the PA outputs are connected to signal transmission lines that diverge in the first and second paths. Each transmission line is connected to a band pass filter and associated matching circuit corresponding to the desired band.
    [7] For the diplexing method to work, the circuit must include a long signal transmission line to carry an amplified signal between the PA and each filtering component. As a first result, both line length and width are critical to circuit performance, so that space on the PCB must be available to accommodate long transmission lines. Secondly, transmission lines of the required length can cause very large losses in the circuit, requiring more power, making the overall circuit less efficient.
    [8] Modifications of the diplexing method eliminated the problem of long and lossy transmission lines, but introduced another inconvenience. This circuit requires very precise discrete components to achieve the high Q values required for proper circuit performance in place of long transmission lines. This reduced the space required for transmission lines on the PCB, but increased the number of high-precision components, significantly increasing the cost of the device.
    [9] The last inconvenience of the diplexing method is the threshold beyond the band impedance of the post PA filter. In order for diplexing to work properly, the band impedance range of the first band filter must be accurately known when the circuit is operating in the second frequency band, and conversely, when the circuit is operating in the first frequency band, the second frequency band The band impedance range of the filter must be known exactly. This is necessary to ensure that the transmission line is of appropriate length and that the PA is observing open circuits in the second RF band while looking at the first RF band path. To ensure that the band impedance range is accurate, the cost and complexity of the filter and the overall network design is increased.
    [10] The use of additional circuitry is problematic because it requires more space in the device and usually wants to reduce costs each time. Existing methods inefficiently generate unwanted power consumption and degrade overall circuit performance. Therefore, there is a need to improve the means and methods for transmitting RF signals in multiple frequency bands using fewer components while maintaining or improving existing transmitter performance levels.
    [1] The present invention relates to the transmission of radio frequency communication signals. More particularly, the present invention relates to a method and apparatus for transmitting an RF communication signal in multiple frequency bands.
    [11] 1 is a block diagram of a conventional dual mode radio frequency transceiver.
    [12] 2 is a block diagram of a transmitter of a wireless communication device according to a preferred embodiment of the present invention.
    [13] 3 shows a variation of impedance of a composite transformer as a function of frequency, showing a variation over the operating range of a transmitter in accordance with a preferred embodiment of the present invention.
    [14] 4 shows the frequency response of the first path according to a preferred embodiment of the present invention.
    [15] FIG. 5 is a Smith diagram corresponding to the frequency response diagram of FIG. 4 showing the impedance of out-of-band and in-band signals in accordance with a preferred embodiment of the present invention. FIG.
    [16] 6 illustrates the frequency response of a second path in accordance with a preferred embodiment of the present invention.
    [17] FIG. 7 is a Smith diagram corresponding to the frequency response diagram of FIG. 6 showing the impedance of out-of-band and in-band signals in accordance with a preferred embodiment of the present invention. FIG.
    [18] The present invention provides a unique method and apparatus for transmitting radio frequency communication signals in multiple frequency bands. This may be applied in wireless communication devices that operate with multiple communication systems, such as cellular communication systems, personal communication systems (PCSs), or satellite communication systems. In a preferred embodiment of the present invention, a dual mode transceiver of a portable radiotelephone tuned to a first RF band tuned to what is typically referred to as an 800 MHz frequency band or a cellular band, and typically referred to as a 1900 MHz band or a PCS band. Transmit the RF communication signal in the second RF band. In addition, the dual mode transceiver is designed to operate under the AMPS of the cellular band or under the TDMA protocol of both the cellular band and the PCS band. However, the transceiver can be designed to operate under communication protocols other than AMPS and TDMA, such as GSM, CDMA, cdma2000, W-CDMA, and the like.
    [19] 1 shows a wireless communication device 100 in accordance with a preferred embodiment of the present invention. This device is a cellular wireless telephone incorporating the present invention. In a preferred embodiment, a frame generator ASIC 102, such as a CMOS ASIC available from Motorola, and a microprocessor 104, such as the 68HC11 microprocessor, also available from Motorola, combine to generate the communication protocols needed to operate in a cellular system. . The microprocessor 104 performs other steps of the wireless communication device, such as performing the steps necessary to generate the protocol, writing to the display 116, receiving information from the keypad 118, or controlling the frequency synthesizer 130. Memory 106, having RAM 108, EEPROM 110, and ROM 112, and preferably incorporated in one package 114, is used to execute. The ASIC 102 processes the audio from the microphone 122 and the audio to the speaker 126 modified by the audio circuit 124.
    [20] 1 also shows a transmitter 128 capable of transmitting RF signals in two separate RF bands required for operation of a dual mode communication device. 2 details a transmitter 128 portion of a wireless communication device. The transmitter 128 consists of a power amplifier 200, a composite transformer 202, a first path 204, and a second path 206. The first path 204 is for transmitting in the first RF band, and the second path 206 is for transmitting in the second RF band. According to a preferred embodiment of the present invention, the first path 204 is tuned to transmit in accordance with the first mode of operation, and the second path 206 is tuned to transmit in accordance with the second mode of operation. The first mode of operation transmits, or transmits, a low band AMPS RF communication signal, and the second mode of operation is tuned to transmit, or transmit, a high band PCS TDMA RF communication signal. The AMPS communication system operates in the range of 824 MHz to 894 MHz, which is divided into 30 kHz channels. TDMA communication systems operate in the range of 824 MHz to 894 MHz for cellular systems and 1850 MHz to 1990 MHz divided into 30 kHz channels for PCS systems. Depending on whether the communication device is in the first mode of operation or the second mode of operation, the RF communication signal is transmitted via the first path 204 or the second path 206, respectively.
    [21] The composite transformer 202 also includes a first node 210, a second node 214, a first transmission line 208 connected between the PA 200 and the first node 210, and a first node 210. It is composed of a parallel capacitor 212 connected between the second node (213). In a preferred embodiment of the present invention, the second node 214 is a common ground. The composite transformer 202 is designed to globally convert the system characteristic impedance for the desired load target in the second RF band. The composite transformer 202 partially converts the impedance of the RF communication signal from the first impedance to the second impedance at the output of the PA 200 when the RF communication signal is in the first RF band. Referring to FIG. 3, the graph shows the change in impedance by the composite transformer 202 in the predetermined frequency range. The composite transformer 202 completely converts the RF communication signal from the first impedance to the third impedance when the RF communication signal is in the second RF band. For example, in a preferred embodiment of the present invention, the first impedance of the PA 200 output is approximately 2 ohms, partially converted to approximately 5 ohms when the RF communication signal is in the first RF band, and the RF communication signal is When in the second RF band, the first impedance is fully converted from approximately 2 ohms to approximately 50 ohms. Since the output impedance of the PA 200 is very low, the high quality (Q) first transmission line 208 is routed to the high Q first capacitor 212 to ensure that the circuitry remains within the designed tolerances and operates properly. Used.
    [22] The first path 204 also includes a second transmission line 216 connected between the third node 218, the fourth node 224, the fifth node 230, the first node 210, and the third node 218. ), A second parallel capacitor 220 connected between the third node 218 and the second node 214, a third transmission line connected between the third node 218 and the fourth node 224, and a fourth node. A third parallel capacitor 226 connected between the second node, and a first filter 228 connected between the fourth node 224 and the fifth node 230.
    [23] Returning to FIG. 4, the frequency response graph shows the frequency response of the first path 204. The frequency response is that the RF communication signal of the first RF band passes through the antenna. 4 also shows that the RF communication signal in the second RF band is significantly attenuated. FIG. 5 is a Smith diagram 500 illustrating a first RF band impedance 402 of a first RF or in-band RF communication signal and a second RF band impedance 404 of a second RF band or out of band communication signal. )to be.
    [24] The second path 206 is a sixth node 238, a seventh node 242, a second filter 232, a sixth node 238 connected between the first node 210 and the sixth node 238. A fourth transmission line 240 connected between the and seventh nodes 242, a fourth parallel capacitor 244 connected between the seventh node 242, and the second node 214, and a seventh node 242 and the seventh node 242. It consists of a third filter 246 connected between the five nodes (230).
    [25] Returning to FIG. 6, the frequency response graph shows the frequency response of the second path 206. The frequency response is that the RF communication signal in the second RF band passes through the antenna. 6 also shows that the RF communication signal in the first RF band is significantly attenuated. FIG. 7 is a Smith diagram 500 illustrating a second RF band impedance 602 of a second RF or in-band RF communication signal and showing a first RF band impedance 604 of the first RF or out of band communication signal. )to be.
    [26] In a preferred embodiment of the present invention, the second filter 232 is a parallel connection of the inductor 236 and the capacitor 234 connected in series between the first node 210 and the sixth node 238. The parallel connection of inductor 236 and capacitor 234 is generally referred to as an LC tank. The second filter 232 is parallel resonant in the first RF band to allow the frequency of the second RF band to pass through. In the preferred embodiment of the present invention, the second filter 232 is resonant in parallel at 800 MHz operating in an open circuit. In the second RF band or high band, the second filter 232 is resonant above, so the ideal component appears as a capacitor. However, by configuring the second filter 232 with a series resonant fifth capacitor 234, the second filter 232 actually appears as a pass circuit in the second RF band or high band. Since the RF communication signal impedance of the second RF band is already converted to a characteristic impedance, for example 50 ohms, at the first node, a nominal Q consisting of conventional components to form the fifth capacitor 234 and the parallel inductor 236. Value virtually eliminates scattering losses. Using conventional components against high Q components and using only two components in the filter allows the circuit to run economically because the cost of the components is kept low.
    [27] When the device is in the first mode of operation and operating in the first RF band, the real part of the impedance irradiated into the second path 206 or the high band path seen by the composite transformer 202 is irradiated to the first path 204. Is much higher than the impedance. Due to this large impedance difference, only a small fraction of the energy in the second path 206 is dispersed or lost. This is done by designing the composite transformer 202 such that the impedance of the RF communication signal is only partially converted in the first RF band or low band in the preferred embodiment. In a preferred embodiment of the present invention, since the impedance of the second path 206 is approximately 500 ohms and the impedance of the first path 204 is 5 ohms, only about 3/10 dB of insertion loss is given to fall within the insertion loss estimate. .
    [28] Since complex transformer 202 only partially converts impedance in the first RF band, impedance conversion must be completed prior to filtering and transmission. Therefore, the second transmission line 216, the third transmission line 222, the second capacitor 220, and the third capacitor 226 of the first path are connected to the fourth node at the second impedance of the first node 210. Designed to complete the impedance conversion to the fourth impedance of 224. The third capacitor 226 has a value that is series resonant when the RF communication signal is in the second RF band or high band. This eliminates the need to control or specify the out-of-band impedance of the first filter 228. The change in load that occurs after the third capacitor 226 is thereby masked by an impedance near zero given in the second RF band.
    [29] Although the invention has been illustrated and described in the foregoing description and drawings, it is to be understood that this description is only an example and that various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Should be. For example, a given method and apparatus is for transmitting RF communication signals, but this may also apply to other forms of wireless communication signals, such as light waves. Although the invention is specifically used in portable cellular radiotelephones, the invention can be applied to any wireless communication device, including pagers, electronic organizers, and computers. The applicant's invention should be limited only by the following claims.
    权利要求:
    Claims (13)
    [1" claim-type="Currently amended] A transmitter for transmitting radio frequency (RF) communication signals in a first RF band and a second RF band:
    A power amplifier (PA) having a PA output for amplifying the RF communication signal in the first RF band and the second RF band;
    A first transmission line coupled between a first node, a second node, the PA output and the first node, and a first parallel capacitor coupled between the first node and the second node, wherein Completely converts the impedance of the RF communication signal from the first node to a first fully converted impedance, and partially converts the impedance of the second RF communication signal of the first RF band from the first node to a second partial converted impedance A first transformer for converting;
    A third node, a fourth node, a fifth node, a second transmission line connected between the first node and the third node, a second parallel capacitor connected between the third node and the second node, and the third node A third transmission line connected between the fourth node, a third parallel capacitor connected between the fourth node and the second node, and a first filter connected between the fourth node and the fifth node, the first filter A first path carrying only the communication signal in an RF band; And
    A sixth node, a seventh node, a third filter connected between the first node and the sixth node, a fourth transmission line connected between the sixth node and the seventh node, between the seventh node and the second node A second path having a fourth parallel capacitor coupled to the second filter and a second filter coupled between the seventh node and the fifth node and delivering only the second RF communication of the second RF band
    Transmitter comprising a.
    [2" claim-type="Currently amended] The method of claim 1,
    The first filter is a low pass filter,
    The second filter is a low pass filter,
    And said third filter is an LC tank filter.
    [3" claim-type="Currently amended] The method of claim 1,
    And wherein the first transmission line has a first impedance, the second transmission line has a second impedance, the third transmission line has a third impedance, and the fourth transmission line has a fourth impedance.
    [4" claim-type="Currently amended] The method of claim 1,
    And wherein the first RF band is in accordance with an advanced mobile phone system (AMPS) and a time division multiple access (TDMA) 800 MHz system, and the second RF band is in accordance with the TDMA 1900 MHz system.
    [5" claim-type="Currently amended] The method of claim 2,
    The LC tank filter further includes a fifth parallel capacitor and an inductor connected in series between the first node and the sixth node in parallel;
    The fifth parallel capacitor is in series resonance when the RF communication signal is in the second RF band,
    The LC tank filter forms an open circuit when the RF communication signal is in the first RF band,
    And said LC tank filter has an effective parallel resistance at least 10 times greater than a second first partial conversion impedance when said communication signal is in said first RF band.
    [6" claim-type="Currently amended] The method of claim 1,
    And the second node is common ground.
    [7" claim-type="Currently amended] The method of claim 1,
    And wherein the first path converts the second impedance into the third impedance between the first node and the fourth node.
    [8" claim-type="Currently amended] The method of claim 1,
    And said third parallel capacitor is resonant in series when said RF communication signal is in said second RF band.
    [9" claim-type="Currently amended] A method of transmitting a radio frequency (RF) communication signal in a first RF band and a second RF band:
    Amplifying the RF communication signal with a power amplifier;
    When the RF communication signal is in a first RF band, partially converting an impedance of the RF communication signal into a first partial conversion impedance;
    Transmitting the first converted RF communication signal having a frequency within the first RF band through a first transmission path;
    Completely converting an impedance of the RF communication signal to a second fully converted impedance when the RF communication signal is in the second band; And
    Transmitting the second converted RF communication signal having a frequency in the second band through a second transmission path
    Method comprising a.
    [10" claim-type="Currently amended] The method of claim 9,
    Amplifying the RF communication signal in the first and second RF bands with only one of the PAs.
    [11" claim-type="Currently amended] The method of claim 9,
    And completing the impedance conversion of the first partial conversion impedance of the RF communication signal to the second impedance with the first transmission path.
    [12" claim-type="Currently amended] The method of claim 9,
    To the LC tank filter when the RF communication signal is in the second RF band, to cause the RF communication signal to pass through the second transmission path, and to the LC tank filter when the RF communication signal is in the first RF band Generating a parallel resonant circuit to prevent the RF communication signal from passing through the second transmission path.
    [13" claim-type="Currently amended] The method of claim 9,
    Generating the effective parallel resistance with the LC tank filter such that an effective parallel resistance is at least 10 times greater than the first partial conversion impedance when the communication signal is in the first RF band. How to.
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    US6389269B1|2002-05-14|
    CN1223094C|2005-10-12|
    EP1305885A4|2006-01-18|
    KR100470582B1|2005-03-10|
    WO2001097389A2|2001-12-20|
    EP1305885A2|2003-05-02|
    WO2001097389A3|2002-05-30|
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2000-06-15|Priority to US09/594,395
    2000-06-15|Priority to US09/594,395
    2001-06-13|Application filed by 모토로라 인코포레이티드
    2001-06-13|Priority to PCT/US2001/019030
    2003-02-05|Publication of KR20030010726A
    2005-03-10|Application granted
    2005-03-10|Publication of KR100470582B1
    优先权:
    申请号 | 申请日 | 专利标题
    US09/594,395|2000-06-15|
    US09/594,395|US6389269B1|2000-06-15|2000-06-15|Method and apparatus for multiple band transmission|
    PCT/US2001/019030|WO2001097389A2|2000-06-15|2001-06-13|Method and apparatus for multiple band transmission|
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