JPH04220817A - Radio communication equipment - Google Patents

Abstract

PURPOSE:To eliminate the need for a transmission/reception separation filter with a steep attenuation characteristic when various radio communication equipments of the time division multiplex transmission system and a power booster are connected. CONSTITUTION:A radio communication equipment 51 is provided with a synthesizer 59 sending a digital modulation signal at the time of transmitting, and receiving a local signal at the time of receiving, and when a power booster 52 is connected to the equipment 51, a modulation RF output from the synthesizer 59 is sent to the power booster 52 as the transmission signal, the local signal from the synthesizer 59 is inputted to a reception mixer 7 in the power booster 52 as the reception signal, converted into an IF signal and inputted to an IF stage o the radio communication equipment 51, then the frequency difference of transmission reception is increased and the filter with a steep attenuation characteristic is not required.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication device using a time division multiplex transmission method for mobile communications such as mobile phones and car phones.

0002

BACKGROUND OF THE INVENTION With the rapid development of the field of mobile communications such as car phones and pagers, there has recently been a demand for their use in a wide range of application fields such as mobile phones and portable facsimiles. Additionally, mobile phones can amplify their RF output by connecting to a power booster installed in the car.
It is now possible to use it as a car phone. Furthermore, digitalization is increasing the capacity of mobile radios and making it possible to directly connect them to digital communication networks such as ISDN.

FIG. 2 shows an example of a simple block diagram of a conventional time division multiplex transmission type digital mobile phone. The transmitting frequency of the mobile phone is 890 to 915 MHz, and the receiving frequency is 935 to 960 MHz, and RF channels are allocated within these frequency bands at intervals of 200 KHz. The maximum transmitting output is 2W, and the 1st of the receiving system
The IF uses approximately 70 MHz, and the 2nd IF uses approximately 1 MHz.

Next, the operation of the configuration shown in FIG. 2 will be explained. The received signal received by the antenna 3 is supplied to the receiving section 22 via the antenna duplexer 4. The receiving section 22 converts the received signal into an intermediate frequency based on the local oscillation signal generated by the synthesizer 17, and demodulates it in the demodulator 24. The demodulated signal passes through the private speech section 27, and then passes through the channel codec 28,
Each signal is digitally encoded by a speech codec 29. The digital code is converted into an analog signal by the D/A converter 31, and then sent to the receiver 35 by the audio signal control section 32.
, controls the speaker 36 and receives it as an audio signal. 3
3 is a volume for adjusting the amount of audio signal.

On the other hand, during transmission, the audio sampled by the microphone 34 passes through the audio signal controller 32 and is sent to the A/D converter 3.
0 is converted into a digital signal and speech codec 2
9. Secret speech part 2 decoded by channel codec 28
7, the burst signal is mixed by a burst generator 25, and modulated by a modulator 23. The modulated signal is frequency-converted by the local oscillation signal from the synthesizer 17 in the transmitting section 21, and is transmitted from the antenna 3 via the antenna duplexer 4.

[0006] In the time division multiplex transmission system, an RF channel with an interval of 200 KHz is time-divided as shown in FIG.
It is designed so that you can get two calling channels. Since transmission and reception are performed alternately using burst signals, transmission and reception are performed alternately in the mobile phone and are digitally processed.

[0007] Furthermore, the mobile phone is 8W or 20W.
A power booster is used to power up the phone and use it as a car phone.

FIG. 4 shows an example of a block diagram of a conventional power booster. Note that the connection between the mobile phone and the power booster is usually made using an RF coaxial cable 19 that is used for both transmitting and receiving signals.
This is performed using several signal lines 20 and a power cable 41 that control transmission power, timing, etc.

The transmission signal sent from the antenna duplexer 4 of the mobile phone 1 is applied to the transmission/reception separation filter 40 via the RF coaxial cable 19, and the transmission signal is separated and sent to the transmission filter 11, the power amplifier 10, and the power amplifier 10. sensor 9
The signal is then supplied to the antenna 8 from the antenna duplexer 2. The amplification degree of the power amplifier 10 is controlled by the output of the power sensor 9.

On the other hand, the reception signal received by the antenna 8 is supplied to the low noise amplifier 5 via the antenna duplexer 2, and after being amplified, it is passed through the reception filter 6 and the transmission/reception separation filter 40.
The antenna is added to the antenna duplexer 4 of the mobile phone 1 through the . The subsequent operations are the same as in FIG.

[0011]

[Problems to be Solved by the Invention] However, when attempting to connect a mobile phone and a power booster by the above means, the power booster requires a transmission/reception system that separates the transmitted signal and the received signal, which has the same performance as an antenna duplexer. A separation filter 40 is required. The upper limit of the transmitting frequency band is 915MHz and the lower limit of the receiving frequency band is 935M.
Since they are separated by only 20 MHz, a steep attenuation characteristic is required to separate them. Such filters are expensive and tend to have large components. Furthermore, the cable length between the mobile phone and the power booster is not constant depending on the location where the power booster is installed, the type of car, etc., and as a result, the amount of RF signal attenuation in this portion is not constant. This greatly affects the noise figure of the receiving system in particular, making it difficult to design the product.

[0012] The present invention solves these problems, and aims to provide a wireless communication device that is small and inexpensive, and whose performance is not affected by the length of the cable between the mobile phone and the power booster.

[0013]

[Means for Solving the Problems] In order to achieve the above object, the present invention transfers a transmission signal from a wireless communication device to a power booster as an RF signal, and transfers a reception signal to an IF signal within the power booster. The configuration is such that the data is converted and then delivered to the wireless communication device.

[0014]

[Operation] Therefore, according to the present invention, even if the RF band transmission signal and the IF band reception signal are transmitted using the same cable, the transmission signal and the reception signal are separated because of the large frequency difference. There is no need for a filter with steep attenuation characteristics for this purpose. The filter in this case can be small and inexpensive. Furthermore, the loss of the IF signal in the receiving system increases or decreases as the cable length changes, and the noise figure of the receiver does not change much due to this.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which a mobile phone 51
This shows the connection of the power booster 52. In the power booster 52, 8 is an antenna, 2 is an antenna duplexer, 5 is a low noise amplifier, 6 is a reception filter,
9 is a power sensor, 10 is a power amplifier, and 11 is a transmission filter, which are the same as each part in FIG. 7 is a mixer, 14 is an IF (intermediate frequency) amplifier, 13 is a combiner, and 15 and 16 are buffer amplifiers.

In the mobile phone 51, 3 is an antenna;
4 is an antenna duplexer. 53 is a low noise amplifier,
54 is a reception filter, 55 is a mixer, 56 is a switch,
57 is an IF filter, and 58 is an AGC amplifier, which correspond to the receiving section 22 in FIG. 59 is a synthesizer,
The synthesizer 59 switches the frequency according to the timing of transmission and reception, and at the timing of transmission, digital modulation is applied by the transmission data from the conventional baseband section 67. Upon reception, synthesizer 59 generates a first local signal. 60 and 61 are buffer amplifiers, 62 is a switch, 63 is a combiner,
64 is a transmission filter, 65 is a power amplifier, and 66 is a power sensor. Buffer amplifier 60, transmission filter 6
4, a power amplifier 65, and a power sensor 66 constitute the transmitter 21 of FIG. The baseband section 67 consists of the modulator 23 to speaker 36 shown in FIG.

When the mobile phone 51 is connected to the power booster 52, the switches 56 and 62 in the mobile phone 51 are switched to the power combiner 63 side. synthesizer 59
The 900 MHz band signal is transmitted to the buffer amplifier 61, switch 62, combiner 63, and power booster 52 side, and the signal is used within the power booster 52 as a transmission signal when transmitting and as a first local signal when receiving. Ru. That is, during transmission, the output of the modulator 23 obtained in the same manner as in FIG.
3, passes through a buffer amplifier 12 as a transmitter, a transmission filter 11, a power amplifier 10, a power sensor 9,
The signal is transmitted by antenna 8 via antenna duplexer 2 .

On the other hand, during reception, the output of the synthesizer 59 is applied to the mixer 7 as a first local signal through the switch 62, the combiners 63 and 13, and the buffer amplifier 16. In the mixer 7, the signal received by the antenna 8 is mixed with the received signal that has passed through the antenna duplexer 2, low noise amplifier 5, and reception filter 6, and is converted to an intermediate frequency, passes through the IF amplifier 14, and is sent to the combiner 13, 63, and the switch. 56, an IF filter 57, an AGC amplifier 58, and is received by a baseband section 67. The operation in the baseband section 67 is similar to that in FIG.

When the power booster 52 is not connected,
The operation of the mobile phone 51 is as follows. switch 56
, 62 to the combiner 63, the switch 56 connects the mixer 55 and the IF filter 57 to the switch 6
2 connects the buffer amplifier 12 and mixer 55, respectively.

[0020] At the time of transmission, the transmission output is a buffer amplifier 60,
Transmission filter 64, power amplifier 65, power sensor 6
The signal is supplied to the antenna duplexer 4 via a transmitting section consisting of 6, and is transmitted from the antenna.

On the other hand, during reception, the signal passes through the antenna duplexer 4, the low noise amplifier 53, and the reception filter 54, and is then sent to the mixer 55.
The received signal applied to the IF
The signal passes through a filter 57 and an AGC amplifier 58 and is added to the baseband section 67.

According to the above embodiment, the RF band transmission signal and the IF band reception signal are mixed using a combiner, the two types of signals are transmitted using the coaxial cable 19, and then separated again by the combiner. Since this method is used, the combiners 13 and 63 can be realized in a small size and at low cost using a simple filter circuit. In addition, the noise figure of the receiving system varies greatly depending on the circuit configuration from the antenna 3 of the power booster 52 to the IF amplifier 14, but since the subsequent combiner 13 and coaxial cable 19 have little influence, it depends on the length of the coaxial cable 19. This prevents reception performance from being greatly affected.

[0023]Although the above embodiment takes a mobile phone as an example, it goes without saying that the present invention can be applied to other wireless communication devices.

[0024]

[Effects of the Invention] As shown in the above embodiment, the present invention realizes a small and inexpensive filter in the power booster, and furthermore, the receiving performance does not change depending on the length of the coaxial cable between the radio and the power booster. This is effective, and it is possible to provide a compact, high-performance, and inexpensive wireless communication device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a wireless communication device in an embodiment of the present invention.

[Fig. 2] A block diagram showing an example of a conventional time division multiplex transmission digital car phone mobile device.

[Figure 3] Conceptual diagram showing an example of the concept of time division multiplexing

[Figure 4] Block diagram showing an example of a conventional power booster

[Explanation of symbols]

2, 4 Antenna duplexer 6 Reception filter 7 Mixer 11 Transmission filter 13 Combiner 54 Reception filter 55 Mixer 56 Switch 59 Synthesizer 62 Switch 63 Combiner 64 Transmission filter 67 Baseband section

Claims (3)

[Claims] 1. A wireless communication device comprising a wireless communication device and a power booster, the wireless communication device including a transmitting means for transmitting a modulated signal, a communication means for receiving a received signal and converting it into an intermediate frequency signal,
The power booster includes a synthesizer that generates a signal that operates as a modulated signal during transmission and as a local signal during reception, and a first combiner selectively connected to the receiving means and the synthesizer. The apparatus comprises: an amplifying means for amplifying a transmission signal from the radio communication device; a converting means for converting the received radio signal into an intermediate frequency signal; and a second combiner connected to the amplifying means and the converting means. In the wireless communication device, the first combiner and the second combiner are connected by a high frequency cable. 2. The power booster according to claim 1, wherein a synthesizer output of the wireless communication device is used as a local signal of the conversion means of the power booster, and the output of the exchange means is inputted to an intermediate frequency stage of the reception means of the wireless communication device. Wireless communication device. 3. A wireless communication device includes an antenna duplexer connected to an antenna, a frequency conversion means for converting the frequency of a received signal to an intermediate frequency, a transmission means for processing a transmission signal to be transmitted from the antenna, and an intermediate frequency. demodulates the frequency signal,
The wireless communication device according to claim 1, further comprising a baseband section that creates a transmission modulation signal.