JPH0730957A - Receiver - Google Patents

Abstract

PURPOSE:To reduce current consumption in the case of a high reception level and to extend the talking distance in the case of a low reception level by comparing the quantity between a reception electric field strength and a set reception electric field strength, thereby controlling a changeover section switching the connection of a low noise amplifier section. CONSTITUTION:When a reception electric field strength RSSI sent from a 2nd reception section 4 is smaller than a setting RSSI, a control section 6 sends a switching control signal to a changeover section 7 to apply an output of a branch section 1 to a 1st frequency conversion section 3 via two-stages of low noise amplifier sections 2, 5. When the RSSI sent by the reception section 4 is larger than the setting RSSI, the control section 6 gives the switching control signal to the changeover section 7 and an output of the branch section 1 is fed directly to the conversion section 3 not through the amplifier sections 2, 5. When the transmission RSSI from the reception section 4 is between the 1st and 2nd setting RSSI, the control section 6 gives an output of the branch section 1 to the conversion section 3 via only the amplifier section 2. Thus, low current consumption is attained in the case of a high reception level and talking distance is extended in the case of a low reception level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver used in a mobile radio system. Mobile radio system,
In particular, the less the power consumption of a receiver used in a mobile phone or the like, the longer the standby time, and the longer the sensitivity of the receiver, the longer the communication distance. Therefore, it is necessary to reduce the power consumption of the receiver and increase the reception sensitivity to extend the communication distance.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram of a conventional example. In the figure, for example, a received signal in the 800 MHz band, which is input via the receiving filter 111 which is a component of the antenna ANT and the demultiplexing unit 11, is amplified by the low noise amplifier 21, and then the fixed attenuator (P
AD ₁ ) 22, through bandpass filter 31 and added to mixer 31.

Since the local oscillation signal is also applied to the mixer 31 via the band pass filter 32, it is frequency-converted into a reception signal in the first intermediate frequency band (for example, 90 MHz band) and then a fixed attenuator (PAD ₂ ) 34, bandpass filter for the first intermediate frequency band
35, via fixed attenuator 36, frequency conversion, amplification, demodulation function and received field strength (Received Signal Strengh Indicato
rSI (hereinafter abbreviated as RSSI)) is added to the IFIC 41 which is an integrated circuit having a function of outputting. Therefore, the demodulated signal and the RSSI of the DC voltage corresponding to the reception level are extracted from the IFIC.

Here, the fixed attenuators 22, 34 and 36 are for adjusting the impedances on the input and output sides. After the antenna, the overall noise figure (NF) is, for example, about 7.3 dB, and the reception level is 0 dB when the mobile unit approaches the base station.
Above m, there is a level change of about –120 dBm and 120 dBm when moving far.

[0005]

As described above, since the circuit configuration of the receiver is fixed, all the constituent elements are in the operating state even when the reception level is high, and the standby time of the receiver is short. . Further, although the call distance is determined by the noise figure of the entire receiver, there are two problems that it is impossible to extend the call distance because the circuit configuration does not change.

An object of the present invention is to reduce current consumption when the reception level is high and to extend the communication distance when the reception level is low.

[0007]

FIG. 1 is a block diagram showing the principle of the present invention. In the figure, 1 is a demultiplexing unit, 2 is a first low noise amplifying unit, 3 is a first frequency conversion unit for frequency-converting a reception signal into a reception signal in a first intermediate frequency band and transmitting the signal, and 4 is an input. It is a second receiving unit that frequency-converts a received signal in the first intermediate frequency band into a received signal in the second intermediate frequency band, amplifies the signal, and sends out a received field strength (RSSI) corresponding to the received level.

Also, 5 is a second low noise amplifying section for amplifying the output of the first low noise amplifying section and sending it to the first frequency converting section, and 7 is a first low noise amplifying section according to the switching control signal to be applied. A switching unit for switching the connection between the constituent elements of the receiving unit and disconnecting the voltage supply to the elements that are not connected, 6 corresponds to various comparison results of the received electric field strength and the set received electric field strength. A table of switching control signals to be transmitted is held, and when the comparison result is obtained by comparing the magnitude of the input received electric field strength with the set received electric field strength, the corresponding switching control signal is used by using the table. Is sent to the switching unit.

[0009]

In the present invention, the first receiving section is provided with the second low noise amplifying section, and the switching section and the control section are provided.

Then, the control unit controls the RSSI sent by the IFIC.
However, when a comparison result is obtained in which it is smaller than the first setting RSSI (for example, D ′ in FIG. 3), the switching control signal is sent to the switching unit to output the demultiplexing unit with two stages of low noise. It is configured to be added to the first frequency conversion unit via the amplification unit. As a result, the noise figure of the entire receiver is lowered, and the communication distance is extended by the improved noise figure.

Also, the RSSI sent by the IFIC is the second setting.
When the comparison result is obtained that it is larger than RSSI (for example, A ′ in FIG. 3), the switching control signal is sent to the switching unit and the output of the demultiplexing unit is not directly passed through the two low noise amplification units, but directly. , And is configured to be added to the first frequency converter. At this time, since the voltage is not supplied to the two unused low noise amplifiers,
The current consumption is reduced and the standby time of the receiver is increased.

The RSSI transmitted by the IFIC is the first set RS.
When the result of comparison between SI and the second RSSI is obtained, the output of the demultiplexing unit is added to the first frequency converting unit via the one-stage low noise amplifying unit, as in the conventional example. I made it up. At this time, the voltage is not supplied to the unused low noise amplifier.

As a result, it is possible to reduce the current consumption when the reception level is high and to extend the communication distance when the reception level is low.

[0014]

2 is a block diagram of an embodiment of the present invention, and FIG.
4 is an operation diagram of the control unit in FIG. 2, and FIG. 5 is an operation diagram of FIG.

Here, the low noise amplifier 21 and the fixed attenuator 22 are
The components of the first low noise amplifier 2, the low noise amplifier 51,
The constant attenuator 52 is a component part of the second low noise amplifying section 5, that is, a switch.
Ji SW ₁₁, SW₁₂, SW_{twenty one}, SW_{twenty two}, SW₃Is a component of the switching unit 7.
Is. Also, the same reference numerals indicate the same symmetrical objects throughout the drawings.
You

The operation of FIG. 2 will be described below with reference to FIGS. 3 to 5. The parts described in detail above will be briefly described, and the part of the present invention will be described in detail. In addition,
The switching control signals for controlling the operations of the switches SW ₁₁ , SW ₁₂ , SW ₂₁ , SW ₂₂ and SW ₃ in FIG. 2 are CONT ₁₁ , CONT ₁₂ , CONT ₂₁ and C.
Use ONT ₂₂ and CONT ₃ .

As shown in FIG. 4, the control unit 6 in FIG. 2 includes a CPU 81, a program ROM 62, and a switching control signal transmitting portion.
It consists of 63, interface 64, RAM 65, and memory 66 that stores the standard RSSI.
A program for performing the operation of
RSSI B´, D´ and reference RSSI C´, A´ are stored,
The former is used when the reception level decreases and the latter is used when the reception level rises. Note that D '<B' and C '<A'.

Further, an example of the relationship between the reception level and RSSI is
As shown in Fig. 3, in the case of 1-stage low noise amplifier (1 stage LNA), the solid line, in the case of 2 stage low noise amplifier (2 stages of LNA), the dotted line, when adding the received signal directly to the mixer (top mixer), the dashed line , Respectively. (1) Configuration of one-stage low-noise amplifier (initial state) First, in the initial state immediately after the power is turned on, the control unit 6
As shown in Fig. 5-, H level CONT ₁₁ , CONT ₂₁ and L level CONT ₃ are sent out, so switches SW ₁₁ and SW ₂₁ are in the dotted line state, and SW ₃ is in the solid line state. The configuration is a one-stage low noise amplifier having only the same low noise amplifier 51 as the above. Further, the switch SW ₁₂ is turned off (dotted line), and the switch ₂₂ is turned on, so that no voltage is applied to the unused low noise amplifier 21. The noise figure of this circuit configuration is approximately 7.3 dB as described above.

Now, the CPU of FIG.
Below, abbreviated as INF) RSSI entered via 64 (hereinafter,
Input RSSI is abbreviated), and standard RSSI D'and standard RSSI A
Compare the magnitude with ´, but the comparison result is the standard RSSI D´ <RS
If SI <reference RSSI A ', the switching control signal transmission part 63
The switching control signal from the above does not change (see Fig. 3 and Fig. 5-).
See). (2) Two-stage low-noise amplifier configuration (RSSI reduction) However, for example, when the mobile device is affected by an obstacle,
As indicated by a in the figure, the reception level decreases and the input RSSI <group
When the CPU detects that it has become quasi RSS ID ', the control unit
Is the L level CONT₁₁, CONT_{twenty one}, CONT₃Is sent,
Switch SW₁₁, SW _{twenty one}, SW₃Is a solid line
It has a two-stage configuration of sound amplifiers 21 and 51. Also, switch S
W₁₂, SW_{twenty two}Turns on (solid line), and the two low noise
A voltage is applied to the width device (see Fig. 5-).

The noise figure in this case is about 5.9 dB,
The reception sensitivity is increased by about 1.4 dB compared to the case of item (1). Therefore, as shown in the lower left part of Fig. 3, the input RSSI rises and then falls again, but the call distance is extended by about 1.4 dB. (3) 1-stage low noise amplifier configuration (RSSI increase) Here, the mobile station is no longer affected by obstacles,
As shown in b), the reception level rises and the input RSSI> reference
When it becomes RSSI C ', as in the case of (1) from the switching control signal sending part 63, H level CONT ₁₁ , CONT ₂₁ , L level CON
Since T ₃ is sent out, the switches SW ₁₁ and SW ₂₁ are in the dotted line state,
SW ₃ is in the state of a solid line, and has a one-stage low-noise amplifier configuration including only the low-noise amplifier 51. However, input RSSI <reference RS
At SI C ', the configuration of the two-stage low-noise amplifier remains the same (see Fig. 5-). (4) Mixer direct connection configuration (RSSI increase) As the mobile unit further approaches the base station, the reception level increases,
When the input RSSI> reference RSSI A ', from the switching control signal sending part 63, H level CONT ₁₁ , CONT ₃ , L level C
Since the ONT ₂₁ is sent, the switches SW ₁₁ and SW ₃ are in the dotted line state, and the SW ₂₁ is in the solid line state, and the output of the demultiplexing unit 11 is directly sent via the fixed attenuator 52 to the first frequency conversion unit. It becomes the composition added to 3. At this time, the switches SW ₁₂ and SW ₂₂ are turned off (dotted line), so that no voltage is applied to the two low noise amplifiers and the current consumption is reduced (see FIG. 5-).

In this case, the noise figure is about 11 dB, which is about 4 dB lower than that in the item (1). However, in the case of the FM receiver, if the reception level is above a certain level even if the reception sensitivity is deteriorated, stable demodulation is possible. Then, (S + N + D) / (N + D) satisfies the specified value. Where S
Is the signal, N is the noise, and D is the level of the distortion component. (5) 1-stage low noise amplifier configuration (RSSI drop) As the mobile station moved away from the base station, the reception level dropped and the input RSSI <reference RSSI B ', as shown in Fig. 3a.
Then, the switching control signal sending part 63 sends H level CONT ₁₁ , CONT ₂₁ and L level CONT ₃ as in the case of (1), so that the switches SW ₁₁ and SW ₂₁ are in the dotted line state, SW ₃ Becomes a state of a solid line, and has a configuration of a one-stage low noise amplifier including only the low noise amplifier 51 shown in the item (1). But enter RS
If SI> standard RSSIB ', keep the mixer directly connected (see Figure 5-).

Here, when comparing the magnitude of the input RSSI and the reference RSSI, by adding hysteresis to the reference RSSI, unstable operation of the switches SW ₁₁ , SW ₁₂ , SW ₂₁ , SW ₂₂ and SW ₃ can be achieved. It can be eliminated and stable switch switching can be performed.

If a comparator is used and the reference voltage is controlled by software, it is possible to provide a hysteris at two points. That is, when the electric field is weak, the low noise amplifier 2
As the double superheterodyne system with multiple stages, the reception sensitivity is improved to extend the communication distance, and the current consumption can be reduced by switching between the strong electric field mode and the top mixer system.

[0024]

As described in detail above, according to the present invention, there is an effect that the current consumption is reduced when the reception level is high and the communication distance is increased when the reception level is low.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is an operation explanatory diagram of FIG. 2;

4 is an example of a configuration diagram of a control unit in FIG.

5 is an operation explanatory diagram of FIG. 4;

FIG. 6 shows a configuration diagram of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Demultiplexing part 2 1st low noise amplification part 3 1st frequency conversion part 4 2nd receiving part 5 2nd low noise amplification part 6 Control part 7 Switching part

Claims (1)

[Claims] 1. A received signal input through a demultiplexing unit (1) is amplified by a first low noise amplifying unit (2), and then a first intermediate frequency band of a first intermediate frequency band is obtained by a first frequency converting unit (3). A first receiving unit that performs frequency conversion into a reception signal and sends the received signal, and an input reception signal in the first intermediate frequency band that is frequency-converted into a reception signal in the second intermediate frequency band for amplification and reception corresponding to the reception level. In a receiver having a second receiving unit (4) for transmitting an electric field strength (RSSI), a second low-frequency amplifier for amplifying the output of the first low noise amplifying unit and transmitting it to the first frequency converting unit. The noise amplification section (5) and a switching section (7) for switching the connection between the constituent elements of the first receiving section according to the switching control signal to be applied and for disconnecting the voltage supply to the elements not connected. And the switching control signal to be sent according to the result of comparison between various received electric field strengths and the set received electric field strength. When the comparison result is obtained by comparing the input received electric field strength with the set received electric field strength, the table is used to send the corresponding switching control signal to the switching unit. Control unit
(6) A receiver provided with.