JPS63256010A - Mobile radio equipment having frequency stabilizing function - Google Patents

Abstract

PURPOSE:To improve the frequency stabilizing accuracy and the low power consumption by providing a circuit detecting a reception electric field level of a receiver in a mobile radio equipment having a frequency synthesizer offering a local oscillating frequency to the receiver and using a control section so as to control a reference oscillator only when the electric field level is a prescribed value or over. CONSTITUTION:The median of received electric field information including Rayleigh fluctuation detected by a receiver 2, 1 is detected by median detection circuit 2, 2 and given to a temperature compensation crystal oscillator TCXO control section 2, 3, which uses a TCXO control signal (b) so as to control a TCXO control section 1, 6 when the level is a prescribed median level or over based on the information from the circuit 2, 2. Then, the frequency stabilization is applied at all times when the electric field level is a prescribed value or over. Since the prescribed electric field level is set higher in this way and the frequency measurement and the frequency stabilization are conducted only when the received electric field level exceeds the given level, the frequency measurement with very high accuracy is executed stably. Moreover, since the number of times of the frequency stabilization is reduced considerably, the power consumption of the circuit is reduced remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is applicable to communication systems that use angular modulation and require extremely small carrier wave drift, such as narrowband mobile communication in the UHF band. The present invention relates to a mobile radio having a function of automatically controlling a carrier frequency to a predetermined value.

(Prior Art) Carrier wave drift in communication methods significantly deteriorates transmission quality. Conventional techniques for stabilizing the carrier frequency in a mobile radio device having a multi-channel switching function include (1) AFCl using the DC component of a frequency discriminator as frequency control information; (2) receiving stable base station transmission waves; There are techniques such as applying a PLL to a local oscillator based on this signal. However, as stated in Japanese Patent Application No. 168004/1983, it is important to apply these technologies to communication systems that require extremely high carrier frequency stability in mobile radio propagation channels that are unique to mobile communications and are subject to fading. with great difficulty.

Therefore, as a means to solve this problem, Japanese Patent Application No. 61-168004 presents a method of receiving highly stable base station transmission waves and accurately measuring the frequency.
68005, proposed a means to dramatically improve the frequency stability of mobile radio equipment. Figure 1 shows its configuration. A stable base station transmission wave received from antenna 1.1 is frequency-converted by receiver 1-2, passed through IF ratio output noise removal means 1.3, and measured by frequency counter 1.4. The TCXO control unit 1.6 controls the temperature compensated crystal oscillator (T(:Xo)) 1.5 so that 1.7, modulator 1.8, mixer 1.
9. In a mobile radio device that is shared by a transmitter including a power amplifier 1.10, the transmission frequency stability of the mobile radio device can be made equal to the stable base station transmission wave frequency product.

(Problems to be Solved by the Invention) However, in the configuration shown in FIG. 1, ■When the received electric field is low, the frequency control granularity is low or 0, and the frequency counter 1.4 and TCXO control unit 1.5 always operate. Therefore, the power consumption of these circuits cannot be reduced.

The purpose of the invention is to: ■ perform frequency stabilization intermittently only when the received electric field is high (short-term (intermittent operation) to improve frequency stabilization accuracy, or by maintaining this state after 01 frequency stabilization control is completed.
It is an object of the present invention to provide a mobile radio device having a frequency stabilizing device that achieves low power consumption by increasing frequency stabilization control intervals (long-term intermittent operation).

(Means for Solving the Problems) The present invention provides the following advantages: from the received electric field level obtained from the receiver,
A circuit is provided to detect the median or average value, and based on that information, the TCXO control unit performs frequency stabilization operations, and after the frequency stabilization is completed, it retains information for controlling the TCXO. The most important feature is that the operation of the frequency counter and TCXO control circuit is stopped to reduce power consumption.

In conventional technology, frequency control was performed continuously, but
The present invention differs from conventional techniques in that the frequency control operation is performed intermittently.

(Embodiment) FIG. 2 shows an embodiment of the present invention, in which 2.1 is a receiver capable of outputting a received electric field level (a);
2.2 is a median value detection circuit that removes the Rayleigh fluctuation component from the received electric field level and detects the median value or average value (here, the circuit detects the median value, but the average value may also be used) of the received electric field level. 3 is a TCXO control circuit that can take in electric field information from 2.2. The other circuits are the same as those in FIG.

The received electric field information with Rayleigh fluctuation detected in 2.1 has its median value detected in 2.2, and the TCXO controller 2.
3 will be done manually. Here, 2.3 controls 1.6 by the TCXO control signal (b) if it is above a predetermined median level based on the information from 2.2. And always,
Frequency stabilization is performed only when the electric field level is above a predetermined value.

As an effect of the present invention, since a predetermined electric field level is set high and frequency measurement and frequency stabilization are performed only when the received electric field level exceeds this, extremely accurate frequency measurement/stabilization effects can be expected.

The present invention is applicable to the case of correcting an error of an arbitrary local frequency of the n-th stage in a heterodyne receiver (Japanese Patent Application No. 6L
-168004).

FIG. 3 shows another embodiment of the invention. In Figure 3, 3
．． 1 is a TCXO control circuit that can take in signals from the circuit 3.2 that outputs start/stop signals for frequency stabilization control, and 3.3 is a TCX output from the TCXO control section.
This is a sample and hold circuit that holds the O control signal (C), and also has a function of storing the TCXO control signal (b).

3.2, if frequency stabilization operation is required, TC
The signal (d) for controlling the XO control unit is turned on and sent to 3.1 to start frequency stabilization. When the frequency stabilization operation is completed, 3.1 outputs a frequency stabilization completion report signal (e) to 3.2. 3.2 waits for this and transmits the signal (d) that controls the TCXO control unit.
3.1 will be stopped. At this time, 3.1 is T
(: The sample and hold signal (C) that holds the XO control signal (b) at 3.3 is output, and - times of frequency stabilization operations are completed. Since it has a memory circuit that does not erase the TCXO control signal, it is possible to significantly reduce the number of times frequency stabilization control is performed and power consumption.For example, when a mobile radio is turned on, frequency stabilization is always performed. There is no need to perform this operation, and high frequency stability can be obtained by performing the frequency stabilization operation only once a year, for example, when the frequency change of the TCXO becomes noticeable over time.

An advantage of the present invention is that by significantly reducing the number of frequency stabilization operations, the power consumption of the circuit can be significantly reduced compared to conventional techniques.

Further, the present invention shows a basic circuit configuration, and describes a method of frequency stabilization in Japanese Patent Application No. 61-168004.
It is of course possible to apply the embodiment.

(Effects of the Invention) As explained above, the present invention can achieve extremely high frequency stability with low power consumption in a mobile radio device.
It is possible to achieve miniaturization and lower power consumption of mobile radio equipment for mobile communication systems using interleaved channels and mobile communication systems using carrier frequencies of IGHz or higher, and as a result, the talk time of mobile radio equipment using batteries is improved. can greatly contribute to

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional mobile radio device having a frequency stabilization function. FIG. 2 is a diagram showing a mobile radio device that performs frequency stabilization operations intermittently based on reception level information. FIG. 3 is a diagram showing a mobile radio device that performs frequency stabilization operations intermittently. 1.1--Antenna, 1.2--Receiver, 1.3-
...Noise removal means, 1.4'-...Frequency counter, 1
．． 5-TCXOl 1.6-TCXO control section, 1.7
--Frequency synthesizer, 1.8--Modulator, 1.9--Mixer, 1.10-
・・Power amplifier, 2.1-・Receiver, 2.2-・Median value detection circuit, 2.3-TCXO control unit, 3.1・-T
CXO control unit, 3.2--Frequency control start/stop signal generation circuit, 3
．． 3--Sample and hold circuit.

Claims (2)

[Claims] (1) A receiver, a noise removing means for removing noise in its IF output, a frequency measuring means connected to its output, a reference oscillator, and a control section for controlling the reference oscillator according to the output of the frequency measuring means. and a frequency synthesizer that uses the output frequency of the reference oscillator as a reference and provides a local oscillation frequency to the receiver, a circuit for detecting a received electric field level of the receiver is provided,
A mobile radio device characterized in that the control unit performs control only when an electric field level is equal to or higher than a predetermined value. (2) A receiver, a noise removing means for removing noise in its IF output, a frequency measuring means connected to the output thereof, a reference oscillator, and a control section for controlling the reference oscillator according to the output of the frequency measuring means. and a frequency synthesizer that uses the output frequency of the reference oscillator as a reference and provides a local oscillation frequency to the receiver, a frequency control start/stop signal generation circuit that generates a signal to control the control unit. and a sample-and-hold circuit that holds the output of the control section, and performs a frequency stabilization function intermittently.