JPH01284028A - Selective call receiver - Google Patents

Abstract

PURPOSE:To attain pull in surely and quickly by detecting the position of a synchronizing word of a selective call signal during the synchronizing lock period and operating a bit synchronizing circuit only at the synchronizing word reception period only. CONSTITUTION:When the position of a synchronizing word is detected by a bit synchronizing circuit 4a at a point of time of receiving a synchronizing word of a group (n), a control signal is outputted from a collation circuit 4b to a bit synchronizing control circuit 4c and the synchronizing control circuit 4c stops the operation of the bit synchronizing circuit 4a at that point of time. Then the bit synchronizing control circuit 4c operates the synchronizing circuit 4a at each arrival of the reception period of a synchronizing word of each group to apply the locking of the bit synchronization. Even if a received waveform with a space message inserted thereto is changed due to jitter or the like, the bit synchronization is locked accurately and quickly by the synchronizing word only.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a selective call reception system that receives selective call signals obtained by time-division multiplexing multiple types of groups with different transmission speeds for each frame. Regarding machines.

(Prior Art) In recent years, as a new type of selective calling system, a system has been proposed that can make a call by ringing and also transmit and display a message. Figure 4 shows an example of the configuration of a selective call signal to which this type of system is applied.One frame consists of a plurality of groups 1 to n exclusively for ringing calls and a display as shown in Figure 4(a). are time-divided into a plurality of groups n+1 to m. Among these groups, groups 1 to n exclusively for ringing calls each have a synchronization word at the beginning as shown in FIG. 4(b), followed by a plurality of call words 1.
. . . 1 are arranged, and the individual number code of the selective call receiver to be called is inserted into these call words. On the other hand, groups n+1 to m with indications are shown in Fig. 4 (
As shown in C), a synchronization word is placed at the beginning, followed by a plurality of call words 1 to 12, of which the individual number code and message code of the selective call receiver are inserted into the call words 1 to 12. Ru. Further, the transmission speed of the groups n+1 to m with this display is set to be N times the transmission speed of the group exclusively for ringing.

Therefore, when a call request is made to any selective call receiver with display, the base station inserts the individual number code of the selective call receiver into an empty call word of the group to which this selective call receiver belongs, and When a message to be displayed is sent from a person, this message code is inserted and sent.

By the way, in general, a selective call receiver continuously receives selective call signals and performs a synchronization pull-in operation during a synchronization pull-in period such as immediately after power-on, and after completing the synchronization pull-in, it only receives the reception period of the group to which it belongs. So-called battery saving is performed by operating the wireless circuit section to perform reception. During the synchronization pull-in period, the bit synchronization circuit is always operated, thereby performing the bit synchronization pull-in operation using all received signals, regardless of whether they are synchronization words or calling words.

However, such conventional selective call receivers sometimes have the following problems. That is, when the base station transmits a group to which a selective call receiver with display belongs, if there is no message code to be inserted, the base station inserts a blank message "001" for each digit in the message code insertion area.
1' is inserted and sent. However, if a group with such a blank message is inserted,
When a selective call receiver dedicated to ringing calls receives during the synchronization pull-in period, the bit synchronization of this selective call receiver is 1/1 with respect to the blank message inserted in the message code insertion area.
This results in a 2-bit shift, causing bit synchronization, and if this happens multiple times, it may cause synchronization.

(Problems to be Solved by the Invention) As described above, the conventional selective call receiver that belongs to the group with low transmission speed performs a bit synchronization pull-in operation during the synchronization pull-in period, so the transmission speed can be doubled. When a blank message inserted into a set group is received, if the received waveform of this blank message changes due to jitter, etc., the bit synchronization of the receiver may become 1/2 due to the effect.
There is a problem that a 2-bit shift occurs multiple times, causing synchronization.The present invention focuses on this point, and allows a selective call receiver belonging to a group with a slow transmission speed to receive a group with a fast transmission speed. It is an object of the present invention to provide a selective call receiver that prevents synchronization from occurring when the receiver is in use, and thereby enables synchronization reliably and quickly.

[Structure of the Invention] Section (Means for resolving A≠Trouble) The present invention detects the position of the synchronization word of the selective call signal during the synchronization pull-in period, and after the position of this synchronization word is detected, each The bit synchronization circuit is operated only during the group synchronization word reception period.

(Function) As a result, after the selective calling receiver belonging to the group with the slow transmission speed detects the position of the synchronization word during the synchronization pull-in period, the bit synchronization circuit performs the bit synchronization pull-in operation only during the reception period of the synchronization word. Therefore, even if a call word into which a blank message is inserted is received and the received waveform of this blank message changes due to jitter, etc., the effect will not affect the bit synchronization pull-in operation. This makes it possible to reliably prevent the occurrence of bit synchronization.

Therefore, synchronous pull-in can always be performed reliably and quickly.

(Embodiment) FIG. 1 shows the configuration of a selective call receiver in an embodiment of the present invention. This receiver receives a selective calling signal transmitted from a base station (not shown) via a receiving antenna 1 in a radio circuit 2, demodulates the received signal in a demodulation circuit 3, and then introduces it into a control section 4. This control section 4 is
It is composed of a bit synchronization circuit 4a that matches the phase of the internal clock of the receiver with the bit phase of the received signal, a collation circuit 4b, and a bit synchronization control circuit 4c. Among these, the collation circuit 4b collates the individual number code reproduced by the demodulation circuit 3 with the individual number code of the own aircraft stored in advance in the storage circuit 5, and when the two codes match, the code is transmitted via the drive circuit 6. A ringing signal is supplied to the speaker 7 to generate a ringing tone. Further, the collation circuit 4b performs the bit synchronization circuit 4a at the time of synchronization pull-in.
It is determined whether or not a synchronization word is detected by the bit synchronization control circuit 4C, and when a synchronization word is detected, a control signal is output to the bit synchronization control circuit 4C. The bit synchronization control circuit 4C is the matching circuit 4b.
When a control signal is output from the bit synchronization circuit 4a, the bit synchronization circuit 4a is thereafter operated only during the synchronization word reception period to perform a bit synchronization pull-in operation. In addition, 8 is a battery saving circuit, and when a signal to the effect that synchronization pull-in is completed is output from the above-mentioned verification circuit 4b, from then on, it is sent to the above-mentioned radio circuit 2 and demodulation circuit 3 only during the reception period of the group to which the own device belongs. The power supply voltage Vcc of the battery 9 is supplied to perform the receiving operation.

With this configuration, when the subscriber turns on the power of the receiver, the power supply voltage of the battery 8 is supplied to each circuit, and the radio circuit 2 and the demodulation circuit 3 operate continuously as shown in FIG. 2(b). state, and the 111a1 section 4 starts the synchronous pull-in operation. At this time, the bit synchronization circuit 4a detects the synchronization word.

Now, in this state, for example, as shown in FIG.
When the bit synchronization circuit 4a detects the position of the synchronization word at the time when the synchronization word is received, a control signal is output from the verification circuit 4b to the bit synchronization control circuit 4C. As shown in FIG. 2(c), the operation of the bit synchronization circuit 4a is stopped. From then on, the bit synchronization control circuit 4c puts the bit synchronization circuit 4a into an operating state as shown in FIG. let Further, the operation control of the bit synchronization circuit 4a by the bit synchronization control circuit 4C continues even after the receiving phase of the receiver with respect to the selective calling signal is established and the battery saving operation is started, as shown in FIG. 3, for example. It is done.

As described above, in this embodiment, after the position of the synchronization word is detected during the synchronization pull-in period, the bit synchronization circuit 4a is set to the operating state only during the reception period of the synchronization word. It is possible to prevent the bit synchronization pull-in operation from being performed during the period. Therefore, even if a blank message is inserted in the group to which the selective calling receiver with display belongs, and the received waveform of this blank message changes due to jitter, etc., only the synchronization word will be unaffected. This allows bit synchronization to be pulled in more accurately and quickly.

Note that the present invention is not limited to the above embodiments. For example, in the embodiment described above, the operation of the bit synchronization circuit 4a is continued to be controlled even after the start of battery saving, but there is no need to perform any particular control after starting battery saving. In addition, the structure of the selective call signal, the circuit structure of the selective call receiver, etc. can be modified in various ways without departing from the gist of the present invention.

[Effects of the Invention] As detailed above, according to the present invention, the position of the synchronization word of the selective call signal is detected during the synchronization pull-in period, and after the position of the synchronization word is detected, the synchronization word reception of each group is performed. By operating the bit synchronization circuit only during this period, it is possible to prevent a selective call receiver belonging to a group with a slow transmission rate from becoming out of synchronization when receiving a group with a high transmission rate. This makes it possible to provide a selective call receiver that can perform synchronization reliably and quickly.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing the configuration of a selective call receiver in one embodiment of the present invention, FIGS. 2 and 3 are timing diagrams for explaining the operation of the receiver, and FIG.
The figure shows an example of the structure of a selective call signal. DESCRIPTION OF SYMBOLS 1... Reception antenna, 2... Radio circuit, 3... Demodulation circuit, 4... Control part, 4a... Bit synchronization circuit,
4b... Verification circuit, 4c... Bit synchronization control circuit,
5...Memory circuit, 6...Drive circuit, 7...Speaker, 8...N (power saving circuit), 9...Battery. Applicant's representative Patent attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] Time division multiplexing of a first group consisting of a synchronization word and a call word and a second group consisting of a synchronization word and a call word whose transmission rate is set to N times that of the first group. a selective calling receiver that receives a selective calling signal and continuously receives the selective calling signal at least during a synchronization pull-in period; 1. A selective call receiver comprising means for operating a bit synchronization circuit only during the synchronization word reception period of each group after the position of the synchronization word is detected by the method.