JPH03229526A - Automatic reduction system for transmission output in radio telephone set - Google Patents

Abstract

PURPOSE:To save power as a whole device by detecting the S meter output of an intermediate frequency level as the target value of the electric field strength of an antenna input radio wave, and automatically addition/subtraction- controlling the transmission output of transmitters in master/slave units in accordance with the detached distance of the master/slave units. CONSTITUTION:Output voltages in the IF level as against the electric field strength of the reception radio wave, namely, the S meter outputs are in a proportional relation, and they correspond to the detached distance of the master/slave units 100 and 200, whereby the voltages appear as the S meter outputs. Then, they are fetched in as one input signal of a comparator. When the slave unit approaches the master unit, the opportunity of noise occurrence increases if transmission power on a master unit-side is reduced. Thus, a time constant circuit element composed of a capacitor C2 and a resistor R2 delay-operates and a terminal B in CPU is converted to L so that transmission output is gradually reduced. Consequently, automatic control for reducing unnecessary transmission output is attained with the electric field strength of the radio wave corresponding to the detached distance of the master/slave units as a reference.

Description

Detailed Description of the Invention: "Industrial Application Field" The present invention is applicable to small-power wireless telephone devices, which are used to communicate when the range of radio waves is limited to approximately 100 meters at most, when the parent and slave devices are in close proximity. This device is suitable for a radio telephone device that aims to save power by automatically reducing the transmitting output of the parent and the handset depending on the receiving radio wave strength of the handset and the handset depending on the separation distance. .

``Prior art'' Generally, wireless transmission between a parent and a handset attached to a wireless telephone device,
Receivers are becoming smaller year by year, especially in order to allow handsets to be moved and used in a portable manner, and the built-in secondary batteries are also becoming smaller, effectively extending the actual operating time as radio equipment. In other words, during the receiver's standby period, the transmitter output is cut off to reduce power consumption as much as possible in order to save power, and the receiver itself is not continuously supplied with power during the standby period. Many use an intermittent power supply method.

However, in the case of low-power wireless telephone devices with a radio wave range of about 100 meters, it is common for calls to be made at a constant transmission power even when the parent and handset are close to each other. Yes, the wireless transmitter and receiver that comes with the base unit is constantly powered by the DC conversion unit, i.e., the power adapter, from the commercial power supply, and the portable slave unit is placed on the charging stand during the standby period when not in use, so it is constantly powered. It is maintained in a supplementary charge state.

Communication via a wireless link between the parent and child devices is possible as long as the separation distance between the two devices is shortened and communication quality does not deteriorate.
Being able to adjust the transmitter output in accordance with the distance and field strength leads to a significant reduction in the power consumption of the entire telephone device.

If the electric field strength is strong, the transmission output is immediately reduced, which may generate noise and cause trouble.

``Problems to be Solved by the Invention'' The purpose of the present invention is to eliminate the disadvantages of the conventional 4'N4, and to avoid deterioration of call quality by adjusting the separation distance between the parent and handset and the electric field of the antenna by hand. The aim is to reduce the power consumption of the entire device.

``The first means to solve the problem'' Thus, the S-meter output, which captures the electric field strength of the antenna input at the intermediate frequency stage of the radio receiver attached to the parent and slave unit, is set as one of the targets, and the separation between the two is set as one goal. The distance is estimated and the magnitude of the S meter output is sent to the central processing unit (
The object of the present invention is achieved by notifying the CPU (hereinafter referred to as CPU) and applying commands to the power supply section of the transmitter so that the CPU can adjust the output of the wireless transmitter.

A radio telephone system implementing the method of the present invention will be explained in detail below.

``Example'' First, in FIG. 1, a base phone is constructed in which a base telephone lOO is connected to a central office line subscriber terminal T1 connected to a telephone exchange via a connecting device 300, and the connecting device has a Wireless transmitter/receiver 1 (X/TX 302 and speaker circuit network,
A line control section 303 consisting of a hook switch, a relay group, etc. (none of which will be described in detail) is built in, and also includes operation switch buttons.

On the other hand, a portable handset 200 that moves within a short distance of about 100 meters is used as a charging stand 20 for the purpose of supplementary charging of the built-in battery and stand function when it is not in use.
It is placed on 1.

Therefore, the wireless transmitter/receiver provided in the parent and handset husband has a circuit configuration shown in FIG. 2, and receives and transmits radio waves via the antenna ANT.

Tx is a transmitting stage, RX is a receiving stage, 2 and 7 are band pass filters (BPF), 2, 8 are) (F AMP, M,

M2 is mixer, 3.4.5 is oscillator, 9.10 is I l
"A~tp, 1t is a detector, 12 is a low frequency amplifier (LF
AMP), 13 is a speaker, and 6 is a microphone.

400 is a control circuit for implementing the transmission output automatic adjustment method of the present invention, 15 is a CPU, 14 is a comparator,
B, , B2 are DCt sources, Q, , Q2 are transistors, C
,,C2,C, is a capacitor, approximately 7. ) also 2. 5. R, , 1L, , 1Y are resistors, R is a variable resistor, and D is a diode.

In the above-mentioned simple configuration, for example, the radio waves emitted by the base unit are received from the antenna ANT2 of the slave unit, and the radio waves are received by the antenna ANT2 of the slave unit, and are passed through bandpass filters 7, 1 (F amplifier 8, first mixer M, IP amplifier 9, second mixer M2, IF amplifier 10, detector 11
．． The signal is transmitted to the speaker 13 via the low frequency amplifier 12.

Therefore, the output voltage at stage 1, that is, the S meter output, is proportional to the electric field strength of the received radio wave as shown in Figure 3, and the voltage as the S meter output corresponds to the separation distance between the parent and child units. The high of the transmit power that appears and is taken as one input signal of the comparator and the CPU is to be controlled by the comparison difference output.

It is configured to determine whether the output is low and issue a command to the drive power source of the transmitter to switch the output to high or low.

If the electric field strength of the radio waves transmitted from the base unit to the slave unit is strong, that is, when the slave unit approaches the base unit and suddenly reduces the transmission power on the base unit side, the chances of noise generation will increase. , the capacitor C2, and the resistor L(, 2) act as a delay time constant circuit element to gradually lower the transmission output.The B terminal of the CPU is converted to "Lo" by the transistor Q.

A circuit time constant is inserted when Q2 is non-conducting.

On the other hand, since the delay effect of the time constant at the time of receiving or transmitting a call is a hindrance, this time the A terminal of the CPU is set to L".
The transmission output is instantly and automatically adjusted to correspond to the electric field strength.

The output of the transmitter is automatically controlled to one transmission power based on the electric field strength, depending on the separation distance between the parent and slave devices, by providing the control circuit Vc in both the parent and slave devices.

In addition, in this embodiment, it is shown that the magnitude of the power supply voltage of the transmitting stage is adjusted.
It goes without saying that the output of FAMP will be trained.

And the transmitter, receiver person, output frequency is usually P L L
Since the signals are synthesized by a synthesizer (not shown), the control circuit may be inserted anywhere between the component that controls the transmitter output and the received radio wave detection means.

``Effects'' Thus, according to the method of the present invention, regardless of the distance between the parent and handset of a low-power wireless telephone device, power consumption is reduced due to the fixed transmission output. In contrast, it is possible to automatically adjust the field strength of radio waves to reduce unnecessary transmission output according to the separation distance between the parent and handset, and to reduce unnecessary transmission output without sacrificing call quality. When using a rechargeable battery as a power source, power consumption can be significantly reduced and the time required for charging can be extended, and it is also possible to further reduce the size of the device. becomes.

[Brief explanation of drawings]

FIG. 1 is a layout diagram of a radio telephone system that implements the automatic transmission output adjustment system of the present invention, and FIG. 2 is a circuit configuration diagram of a wireless transmitter and a receiver provided in the parent and handset husband and wife in FIG. 1. FIG. 3 is a graph showing the relationship between the electric field strength of the radio waves received by the antenna and the S meter output voltage. 100...Main phone, 200 Handset, 202.301
1...XM outlet for i, 201...nayaging stand, 300...connection tearing, 302...wireless transmitting/receiving light device, 303...line control terminal, TI...station line subscriber terminal, 1 .8... H, F A M P , 2.7...
・BPP, 9.1-0...■ FAMP,, M,, M2... Mixer, 3.4 5... Oscillator, ... Detector, 6... Microphone, ■ 2... Low frequency amplifier, ■ Spiral power, ... comparator, ■ 5 ... - Applicant Isera stock

Claims (1)

[Claims] A radio wave link is formed between a base unit connected to a subscriber telephone via a connection device with a built-in wireless transmitter and receiver to the terminal of the telephone office line, and a portable handset that mainly includes a wireless transmitter and receiver. In a wireless telephone system that performs phone calls, the S meter output of the intermediate frequency stage provided in each of the receivers of the parent and child units is detected as the target value of the electric field strength of the antenna input radio wave, and the An automatic transmission power saving system for a wireless telephone device, characterized in that power is saved by automatically increasing or decreasing the transmission output of the transmitters of the parent and handset husband in accordance with the separation distance.