CN1113555C - Stabilized data correcting function in wireless selective call receiver - Google Patents

Abstract

In a radio selective calling receiver, a receiving section receives a radio selective calling signal to generate an analog demodulated signal. The receiving sections (1a, 1b, 1c) are controlled to be turned on periodically. The A/D converter (1e) converts the analog demodulated signal into a digital signal. A correction circuit (1f) performs a correction function to correct the digital signal based on the target signal, and generates arrival data. The control unit (2) controls the correction circuit to stop the correction operation for a first predetermined period of time after the receiving section is turned on.

Description

A wireless selective calling receiver and method of correcting the data it receives

technical field

The present invention relates to a radio selective calling receiver, and more particularly, to a radio selective calling receiver having a data correction function when converting an analog signal into a digital signal.

Background technique

In a conventional radio selective calling receiver, a data correction operation is performed on a digital signal output from an analog-to-digital signal conversion circuit. The data correction function is often activated during the demodulation cycle of the analog signal, during which the amplification circuit and the demodulation section before the signal conversion circuit operate.

In addition, in the above-mentioned data correction function, since the data correction circuit and the receiving unit operate simultaneously, it is even possible to implement the data correction function in a transient state in which the receiving unit switches between on and off states , the transition in which the frequency of the filter is switched, and it is possible to implement the data correction function during the period when no data is initially output.

That is, such a data correction circuit converts an analog signal into digital data or arrival data and performs a feedback operation to correct the difference between the arrival data and ideal value data. As a result, it is possible to prevent the influence of the surrounding environment and the decline of the call reception percentage due to the variation of each part. However, the data correction circuit always works during the operation of the receiving unit. The data correction unit operates even when the receiving unit is switched between on and off states and when the frequency of the filter is switched. Therefore, erroneous data correction is sometimes performed on arriving data in such a transient state.

A delay unit is described in Japanese Patent Publication (JP-A-showa 62-207984) published for public examination, in which delay errors due to branching of delay lines are effectively compensated. However, a stable data correction function is not described.

Contents of the invention

The present invention proposes a solution to the above-mentioned problems. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a stable data correction method and a stable data correction method of a wireless selective calling receiver.

Another object of the present invention is to provide a radio selective calling receiver which does not perform any error correction.

In order to realize an aspect of the present invention, the wireless selective calling receiver includes: a receiving section for receiving the wireless selective calling signal to generate an analog demodulated signal, so that the receiving section is controlled so that it is turned on periodically; an analog/digital (A/D) converter for converting an analog demodulated signal into a digital signal; a correction circuit for performing a correction function to correct a digital signal based on a target signal and generate arriving data; and a correction circuit for controlling the correction circuit so that in the receiving section A control unit that deactivates the calibration function within a first predetermined period of time after being switched on.

When the radio selective call receiver further includes a filter for setting the frequency band of the demodulated signal according to the transmission rate of the radio selective call signal, the control unit may control the correction circuit so that the frequency band of the demodulated signal is switched for the second predetermined time period Stop the calibration function inside.

When the wireless selective calling receiver further includes a notification unit for notifying the user of the arrival of the arrival data within a third predetermined time period, the control unit may control the correction circuit so as to stop the correction function during the third predetermined time period when the notification unit operates .

The control unit may control the correction circuit to stop the correction function within a fourth predetermined time period when noise is determined to be introduced.

In accordance with another aspect of the present invention, a method of deriving correct arrival data from a radio selective call signal in a radio selective call receiver includes the steps of:

Control the receiving part so that it is switched on periodically;

When the receiving part is turned on, receive the wireless selective calling signal to generate the analog demodulation signal;

Convert analog demodulated signal into digital signal;

performing a correction function to correct the digital signal from the target signal and produce arrival data; and

The correction circuit is controlled to stop the correction function within a first predetermined period of time after the receiving section is turned on.

Description of drawings

FIG. 1 is a block diagram illustrating the basic structure of a wireless selective calling receiver according to an embodiment of the present invention;

2A to 2D are time charts illustrating operations of various parts of a receiving unit in a wireless selective calling receiver according to an embodiment of the present invention;

3A to 3C are time charts for describing the operation of the correction circuit when the frequency of the filter inside the wireless selective calling receiver according to the embodiment of the present invention is switched; and

4A to 4E are timing charts for describing the operation of the correction circuit when noise is introduced into the radio selective calling receiver according to another embodiment of the present invention.

Detailed ways

A radio selective calling receiver of the present invention will be described in detail below with reference to the accompanying drawings.

First, a wireless selective calling receiver according to an embodiment of the present invention will be described. FIG. 1 shows the basic structure of a wireless selective calling receiver according to an embodiment of the present invention.

Referring to FIG. 1 , the wireless selective calling receiver includes a receiving unit 1 , a control unit 2 and a notification unit 3 . The receiving unit 1 includes an antenna 1a, an amplification circuit 1b, a demodulation section 1c, a filter 1d, an A/D converter 1e, and a correction circuit 1f.

An antenna 1a receives a radio signal transmitted from a radio base station to a radio selective calling receiver and outputs it to an amplifying circuit 1b. The amplifying circuit 1b amplifies the reception signal received by the antenna 1a in this way to output to the demodulation section 1c. The demodulation section 1c demodulates the reception signal which has been modulated according to a predetermined method, and demodulates the latter into a baseband signal to output to the filter 1d.

The filter 1d is a low-pass filter and functions to remove noise components contained in the baseband signal as the demodulated signal. The cutoff frequency of filter 1d may be switched according to the transmission rate of the received signal. In this way, the filter 1d outputs to the A/D converter 1e a baseband signal in which noise components are eliminated in accordance with the transmission rate of the received signal. The A/D converter 1e converts the baseband signal supplied as an analog signal from the filter 1d into a digital signal, and outputs it to the correction circuit 1f.

The correction circuit 1f compares the digital signal input from the A/D converter 1e with a reference data signal which is an ideal data signal. If there is a difference in amplitude between the digital signal and the reference data signal, the correction circuit 1f corrects the digital signal based on the comparison result to eliminate the difference. The corrected digital signal is output to the control unit 2 as arriving data.

The control unit 2 controls the receiving unit 1 so that it is switched on periodically. The control unit 2 also controls the filter 1d so that the cutoff frequency of the filter 1d is switched based on the transmission rate of the received signal. The control unit 2 further controls the operation of the notification unit 3 based on the arrival data input from the receiving unit 1 in this way.

The notification unit 3, under the control of the control unit 2, notifies the user that a call is received. For example, the notification unit 3 includes a sound generating unit or a vibration unit for generating a voice in order to notify the arrival of a call or the like.

Next, the operation of the wireless selective calling receiver according to the embodiment of the present invention will be described. 2A to 2D are timing charts describing the operation of each part described above. As shown in FIGS. 2A to 2D , the operation of each part of the receiving unit 1 is controlled by the control unit 2 .

The control unit 2 controls the receiving unit 1 to be turned on or off periodically to receive wireless signals, as shown in FIG. 2A. In this case, the receiving unit 1 is not in a steady state for the first predetermined time period after the receiving unit 1 is turned on. That is, since the receiving unit 1 is in a transient state during the first time period, the receiving unit 1 is not in a stable operating state. Therefore, the control unit 2 controls the correction circuit 1f to stop the data correction operation for the first time period, as shown in FIG. 2D.

When the transmission rate of the baseband signal, that is, the transmission rate of the received signal is switched as shown in FIG. 2C, the control unit 2 also switches the cutoff frequency of the filter 1d according to the transmission rate, as shown in FIG. 2C. In the second predetermined time period after the control unit 2 instructs the filter 1d to switch the cut-off frequency, there is a phase difference in the baseband signal output from the filter 1d. Therefore, the control unit 2 controls the correction circuit 1f to stop the data correction operation within the second predetermined time period after switching from the cut-off frequency, as shown in FIG. 2D .

Next, details of the operation of this stop data correction function of the correction circuit 1f will be described with reference to the drawings. 3A to 3C are timing charts describing the operation of the radio selective calling receiver.

In this embodiment, it is assumed that the transmission rate of the received signal is switched from transmission rate 1 to transmission rate 2 and then to transmission rate 3 when the receiving unit is turned on, as shown in FIG. 2C . In this state, the cutoff frequency of the filter 1d is switched by the control unit 2 from the cutoff frequency f1 to the cutoff frequency f2 to the cutoff frequency f3 corresponding to the transmission rates 1 to 3 . As shown in Figure 2B.

When the receiving unit 1 is switched from the off state to the on state, the baseband signal transmitted to the A/D converter 1e does not have a normal signal level for the first predetermined time period due to the transition state of the receiving unit 1 . The output of the A/D converter 1e is shown in Fig. 3A. The correction circuit 1f is turned on after the first predetermined time period, as shown in FIG. 3B, and then the arrival data signal can be obtained as shown in FIG. 3C.

The baseband signal also has a normal level for the second predetermined time period from the transition of the cutoff frequency of the filter 1d between frequencies 1 to 3. The output of the A/D converter 1e is shown in Fig. 3A. The correction circuit 1f is turned on after the first predetermined time period, as shown in FIG. 3B, and then the arrival data signal shown in FIG. 3C can be obtained.

Although according to the set values of the above-mentioned cutoff frequencies 1 to 3, the time period during which the baseband signal is not in a normal state is, for example, 100 milliseconds. When the cutoff frequency of the filter 1d is switched between frequencies 1 to 3, the phase difference of the baseband signal also occurs due to the switchover of the cutoff frequency 1 to 3, so that the normal arriving data signal cannot be obtained sometimes. For example, this phase difference lasts for a period of 50 milliseconds from when the cut-off frequency of filter 1d switches between frequencies 1 to 3.

A time period during which normal data arrival data is not obtained is preset inside the control unit 2 . As a result, the control unit 2 controls the correction circuit 1F not to operate during the time period. Accordingly, the correction circuit 1f is set to the off-state during the first predetermined time period after the receiving unit 1 is set to the on-state and for the second predetermined time period after the cut-off frequency of the filter 1d is switched, so that Stop the data correction function.

The period of time in which the normally arriving data signal is not obtained is not only the period of time after the receiving unit 1 is turned on and the period of time after the filter 1d is switched. The control unit 2 is in a special state during the period of time when the notification unit 3 operates and the period of time when the user operates a switch or the like.

Next, a wireless selective calling receiver according to another embodiment of the present invention will be described.

Sometimes noise is produced. The control unit 2 determines that such noise has a timing at which the progress of the correction circuit should be stopped, as shown in FIG. 4B . In this case, it will be considered that the control unit 2 sets the correction circuit 1f to an off state to stop the data correction function, as shown in FIG. 4E.

As described above, according to the wireless selective calling receiver of the present invention, the data correction function of the digital signal is stopped for a predetermined period of time from switching of the circuit located in front of the A/D converter. Therefore, erroneous data correction of digital signals can be prevented. Thus, the reliability of the radio selective paging receiver is increased.

When switching the cutoff frequency of the filter to set the frequency band of the demodulated signal, the data correction of the received signal is also stopped. Therefore, identification errors of digital signals in filter switching are reduced, increasing the reliability of the radio selective calling receiver.

In addition, when the circuit located in front of the A/D converter is activated, the data correction of the received signal is also stopped. Thus, any correction error of the digital signal at the time of circuit startup can be prevented.

Also, in the radio selective calling receiver of the present invention, when noise is introduced in the circuit located before the A/D converter, the data correction of the digital signal is stopped. Therefore, it is also possible to prevent the correction error of the digital signal when noise is introduced, and to increase the reliability of the radio selective calling receiver.

Claims (8)

1. A wireless selective calling receiver, characterized in that it comprises: a receiving part for receiving a wireless selective call to generate an analog demodulation signal, wherein the receiving part is controlled to be turned on periodically; A/D converter for converting said analog signal into a digital signal; a correction circuit for performing a correction function to correct the digital signal based on the target signal and generate arrival data; a filter in which baseband of said demodulated signal is set based on a transmission rate of said wireless selective call signal; a notification unit for notifying the user of the arrival of the arrival data; and A control unit for controlling the correction circuit so as to stop the correction function for a first predetermined period of time after the receiving section is turned on. 2. The radio selective calling receiver according to claim 1, wherein said control unit controls said correction circuit so as to stop a correction function within a second predetermined time period after the frequency band of said demodulated signal is switched. 3. The radio selective calling receiver according to claim 1, wherein said control unit controls said correction circuit to stop said correction function during a third predetermined time period while said notification unit operates. 4. The radio selective calling receiver according to any one of claims 1 to 3, wherein said control unit controls said correction circuit to stop said correction function for a fourth predetermined time period when noise is determined to be introduced. 5. A method for calibrating received data of a wireless selective calling receiver, comprising the following steps: Control the receiving part so that it is turned on periodically; receiving a radio selective call signal to generate an analog demodulated signal when said receiving section is turned on; converting the analog demodulated signal into a digital signal; performing a correction function to correct the digital signal based on the target signal and generate arrival data; and The correction circuit is controlled to stop the correction function within a first predetermined period of time after the receiving section is turned on. 6. The method according to claim 5, further comprising a control step for stopping said correction function for a second predetermined time period after the frequency band switching of said demodulated signal. 7. The method according to claim 5, further comprising a control step for stopping said correction function at a third predetermined time period when a user is notified of arrival of said arrival data. 8. A method according to any one of claims 5 to 7, further comprising a control step for stopping said correction function for a fourth predetermined time period when noise is determined to be introduced.

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