JP2826532B2 - Pager system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pager system having an automatic frequency control function, and more particularly to a multicarrier type pager system capable of receiving a plurality of carriers allocated to a specific frequency band.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a configuration of a conventional multi-carrier type pager system. As shown in FIG. 2, the conventional pager system includes a plurality of demodulation units 11.
−0 to 11-N, and can receive subcarriers of a plurality of channels 0ch to Nch allocated within a specific frequency band. The demodulator 11-0 outputs the 0th
The demodulator 11-1 demodulates the subcarrier of the first channel, and the demodulator 11-N demodulates the subcarrier of the Nth channel. These demodulation sections 11-1 to 11-11
-N is an automatic frequency control unit (hereinafter referred to as "AFC unit")
12-0 to 12-N, and receives the received signals received by each demodulation unit.
The signal is supplied to a local oscillating unit 15 described below via 12-N, and the received signal of each channel is demodulated in a stable state.

[0003] In other words, the AFC units 12-0 to 12 -N generate local oscillation control signals that follow the respective received signals and output them to the selection unit 13. The control information corresponding to the system is supplied from the data processing unit 14 to the selection unit 13, and one of the control signals corresponding to the reception channel specified by the control information is selected from the outputs of the AFC units. To the local oscillator 15.

The local oscillating section 15 generates a local oscillating signal in accordance with the control signal and outputs it to each of the demodulating sections 11-0 to 11-N. The reception signal of the designated reception channel is demodulated and supplied to the data processing unit 14, where necessary processing is performed.

[0005]

In the conventional pager system described above, in order to demodulate the received signal of each channel in a stable state, the AFC units 12-0 to 12-1 for each channel are used.
2-N is provided. Also, on the system protocol,
Since a channel to be received is determined by control information from the system, it is necessary to provide a selector 13 for selecting an AFC unit according to the received channel. As described above, the conventional pager system includes an AFC unit for each channel,
It is necessary to provide a selection unit for selecting the FC unit, and there is a problem that the circuit scale is increased and the manufacturing cost is increased. The present invention has been made to solve such a problem.

[0006]

A pager system according to the present invention comprises a plurality of demodulators for individually receiving a plurality of carriers including a constantly present carrier, and a demodulator for receiving a constantly present carrier in the demodulators. An automatic frequency control section connected to the section, and a local oscillation section controlled by the automatic frequency control section to generate a local oscillation signal, and supplies an output of the local oscillation section to each of the demodulation sections to receive a reception signal. Is demodulated.

As described above, the pager system of the present invention
Of the plurality of demodulation units, the AFC unit is connected only to the demodulation unit that receives the control signal of the control channel that is always present in the system, and the AFC unit is configured to perform local oscillation based on the received signal of the control channel that is always present. The local oscillation frequency oscillated from the section is controlled so as to follow this received signal, and the pager system of the present invention supplies the reference frequency signal obtained by such control to each demodulation section and supplies the sub-frequency of each channel. The carrier is configured to be stably received.

As described above, since the AFC section is shared by a plurality of demodulation sections, it is not necessary to provide AFC sections in all demodulation sections, so that the circuit scale can be reduced.
Manufacturing costs can be reduced.

In addition, a data processing unit connected to all of the plurality of demodulation units is provided, and the data processing unit is configured to process received information supplied from the plurality of demodulation units simultaneously or selectively. Is preferred. As described above, since the data processing unit is configured to select a reception channel, there is no need to provide a selection unit for specifying the reception channel, and thus the circuit scale can be further reduced.

[0010]

FIG. 1 is a block diagram showing the configuration of an embodiment of a pager system according to the present invention. FIG.
As shown in (1), the pager system of the present embodiment is configured to be able to receive subcarriers of the 0th channel to the Nth channel. Of these channels, the 0th channel is a control channel that is received to obtain various types of control information and the like from the system, and is a channel in which a subcarrier always exists. The present system has the same number of demodulation units 1-0 to 1-N as the number of these channels.
, The demodulation section 1-1 receives and demodulates the first channel, and the demodulation section 1-N receives and demodulates the subcarrier of the Nth channel.

An AFC unit 2 is connected to a demodulation unit 1-0 which receives a reception signal of the 0th channel where a subcarrier always exists. The AFC unit 2 receives the demodulated signal of the 0th channel supplied from the demodulation unit 1-0, generates a local oscillation frequency control signal, and supplies the control signal to the local oscillation unit 3. The local oscillator 3 generates a reference frequency signal based on the control signal, and outputs it to the demodulators 1-0 to 1-N.

Each of the demodulation units 1-0 to 1-N includes a local oscillation unit 3
Demodulates the sub-carriers of each channel by the reference frequency signal output from. In this case, since the supplied reference frequency signal follows the received signal of the 0th channel in the demodulation unit 1-0 that receives the 0th channel, the received signal can be directly demodulated with this reference frequency signal. . The other demodulation units 1-1 to 1-N cannot demodulate the received signal even if the reference frequency signal is directly mixed with the respective subcarriers. Therefore, the difference between the frequency of each channel and the 0th channel is determined by this reference frequency. The received signal is demodulated using the sum of the signals.

The signals demodulated by the demodulation units 1-0 to 1-N are sent to the data processing unit 4. In this data processing unit 4,
Reception data is recognized by the demodulation signal supplied from each demodulation unit, and simultaneously or selectively for each channel,
Necessary data processing is performed.

As described above, in the pager system with the automatic frequency control function of the present invention, the AFC section is provided in the demodulation section of the control channel where the subcarrier always exists, and the local oscillation section is provided based on the output of the AFC section. , And supplies the reference frequency to the demodulation unit of each channel so that signals of a plurality of channels can be stably received, thereby reducing the size and cost.

[0015]

As described above, in the pager system of the present invention, the AFC section connected to the demodulation section of the control channel in which the subcarrier always exists is shared by the demodulation sections of the respective receiving channels. Therefore, only one AFC unit is required, and a selection unit for selecting an AFC reception channel is not required. Therefore, there is an effect that the circuit scale can be reduced and the manufacturing cost can be reduced as compared with the conventional system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a pager system having an automatic frequency control function of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional pager system having an automatic frequency control function.

[Explanation of symbols]

 1-1 to 1-N demodulation unit 2 AFC unit 3 local oscillation unit 5 data processing unit

Claims (2)

(57) [Claims] 1. A multi-carrier type pager system capable of receiving a plurality of carriers allocated to a specific frequency band, a plurality of demodulation units for individually receiving the plurality of carriers including a constantly existing carrier, An automatic frequency control unit connected to a demodulation unit that receives the constantly present carrier wave in the demodulation unit; and a local oscillation unit that generates a local oscillation signal controlled by the automatic frequency control unit. A pager system having an automatic frequency control function, wherein an output of the section is supplied to each of the demodulation sections to demodulate a received signal. 2. The pager system having an automatic frequency control function according to claim 1, further comprising: a data processing unit connected to all of the plurality of demodulation units, wherein the data processing unit is provided from the plurality of demodulation units. A pager system characterized in that supplied information is simultaneously or selectively processed.