JP3923868B2 - Communication apparatus and communication method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a communication device and a communication method.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a communication apparatus that receives a digital data group in which a transmission side digitizes an audio signal and is distributed and incorporated into a plurality of frames, and reproduces the audio. A frame synchronization signal is included at the beginning of the digital data group transmitted by the transmitting side.
[0003]
The communication apparatus on the audio reproduction side decodes the frame synchronization signal, and establishes frame synchronization with the transmission side for the received digital data group using the frame synchronization signal to detect each frame. Then, the audio signal is decoded in frame units, and the audio is reproduced based on the decoded audio signal.
[0004]
[Problems to be solved by the invention]
In a conventional communication apparatus, when frame synchronization is not established due to fading or the like, the audio signal cannot be correctly decoded. Therefore, received data is invalidated and discarded during a period when synchronization is not established. In this case, there is a silent state. The communication apparatus repeats decoding of the frame synchronization signal until frame synchronization is established. However, if the interval of the transmitted frame synchronization signal is long, the silent state will continue as much. Also, when there is analog or digital data having a different frame configuration in the communication channel, they are regarded as invalid data and are similarly silenced.
[0005]
When the silent state continues as described above, it may be desired to determine whether reception data is not received or frame synchronization is not established. Some communication devices include an S meter that measures the level of received data, and further includes a display lamp that lights or blinks when the level is equal to or higher than a predetermined value. In such a communication device, it is possible to determine whether or not the received data is received even if there is a silence state by checking the indication value of the S meter or visually checking the lighting state of the display lamp. Can do. However, it is necessary to visually check the state of the S meter and the display lamp, which is inconvenient.
[0006]
An object of the present invention is to provide a communication device that is easy to use.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a communication device according to a first aspect of the present invention includes a receiving unit that receives a digital data group in which a transmission target signal is encoded by a transmission side and distributed and incorporated into a plurality of frames. Establishing a frame synchronization for the digital data group received by the receiving means, detecting the frames, a restoring means for restoring the transmission target signal based on a processing result of the synchronization establishing means, A level measuring means for measuring the level of the signal received by the receiving means, and a state in which the level of the signal received by the receiving means is not less than a predetermined value and the frame synchronization is not established based on the measurement result of the level measuring means. A state detecting means for detecting, and a state in which the level is not less than a predetermined value and the frame synchronization is not established by the state detecting means. And a audible tone generating means for generating a predetermined audible sound when it is,
The transmission target signal is an audio signal,
The state detecting means is based on the measurement result of the level measuring means, and the level of the signal received by the receiving means is not less than a predetermined value and the frame synchronization is not established, and the level of the signal is A second state in which the frame synchronization is established above a predetermined value, a third state in which the level of the signal is less than a predetermined value and the frame synchronization is not established, and a level of the signal is less than a predetermined value And the fourth state where the frame synchronization is established, and the audible sound generating means generates the predetermined audible sound when the first state is detected, and the second state. When sound is detected, sound corresponding to the sound signal restored by the restoration means is generated, and no sound is generated when the third state or the fourth state is detected .
[0009]
The digital data group may be transmitted wirelessly from the transmission side.
[0010]
In order to achieve the above object, a communication method according to a second aspect of the present invention receives a digital data group in which a transmission target signal of an audio signal is encoded by a transmission side and dispersed and incorporated into a plurality of frames. A communication method for establishing frame synchronization for the digital data group to detect each frame and restoring the transmission target signal based on the result,
A first state in which the level of the received signal is measured, the level is not less than a predetermined value and the frame synchronization is not established, and a second state in which the level is not less than a predetermined value and the frame synchronization is established. Detecting a state, a third state in which the level is less than a predetermined value and the frame synchronization is not established, and a fourth state in which the level is less than a predetermined value and the frame synchronization is established;
A predetermined audible sound is generated when the first state is detected, a sound corresponding to the restored transmission target signal is generated when the second state is detected, and the third state or No sound is generated when the fourth state is detected .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a communication device and a communication method according to embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a configuration diagram showing a communication apparatus according to the first embodiment of the present invention. FIG. 2 is a circuit diagram showing a configuration example of the S meter 10 in FIG.
[0012]
This communication apparatus includes an antenna 1, a reception processing unit 2, a frame synchronization unit 3, an audio data extraction unit 4, a decoding unit 5, a switch 6, a synthesizer 7, an amplifier 8, and a speaker 9. And an S meter 10 and a state detector 11.
[0013]
This communication device is a device having a function of reproducing sound, and the communication device T on the transmission side modulates a carrier wave by a digital data group DT in which a digitized sound signal is divided into a plurality of frames. The modulated wave obtained in this way is transmitted wirelessly. The antenna 1 receives a signal transmitted from the transmission side T.
[0014]
The reception processing unit 2 includes a down converter 2a, a demodulation circuit 2b, a bit synchronization circuit (bit synchronization) 2c, and the like. The down converter 2a converts a signal received via the antenna 1 into an intermediate frequency signal, and a demodulation circuit 2b performs demodulation to extract a baseband signal. The bit synchronization circuit 2c performs bit synchronization of the baseband signal and outputs bit string data S2 corresponding to the digital data group DT.
[0015]
The frame synchronization unit 3 and the audio data extraction unit 4 form synchronization establishment means and are connected to the reception processing unit 2. The frame synchronization unit 3 is configured by a DSP (Digital Signal Processor) or the like, and establishes frame synchronization with respect to the bit string data S2 to detect each frame. The audio data extraction unit 4 is constituted by a DSP or the like, and extracts digitized audio data from a plurality of frames.
[0016]
The decoding unit 5 includes a digital / analog conversion circuit or the like, and decodes the digital audio data output from the audio data extraction unit 4 to generate an analog audio signal.
The switch 6 is a three-state switch connected to the output terminal of the decoding unit 5, the output terminal of the synthesizer 7, and the output terminal of the state detection unit 11. The switch 6 switches the output signal of the synthesizer 7 and the output signal of the decoding unit 5 based on the switching signal output from the state detection unit 11 or does not output a signal for generating sound.
[0017]
The amplifier 8 is connected to the switch 6 and amplifies the signal given from the switch 6.
The speaker 9 is connected to the amplifier 8 and, together with the switch 6 and the amplifier 8, serves as an audible sound generating means and generates sound. The synthesizer 7 generates a signal that becomes a predetermined audible sound.
[0018]
The S meter 10 is means for measuring the level of the received signal in this communication device, and is connected to, for example, the output terminal of the down converter 2 a in the reception processing unit 2.
The S meter 10 shown in FIG. 2 includes a cutoff capacitor 10a having one electrode connected to an input terminal. The other electrode of the cut-off capacitor 10a is connected to one end of the resistor 10b, one end of the resistor 10c, and the base of the NPN transistor 10d. The resistors 10b and 10c set the bias voltage of the transistor 10d. The other end of the resistor 10b is grounded, and the other end of the resistor 10c and the collector of the transistor 10d are connected to a power source.
[0019]
The emitter of the transistor 10d is grounded via the emitter resistor 10e and is connected to one electrode of the cutoff capacitor 10f. The other electrode of the cut-off capacitor 10f is connected to the anode of the diode 10g and the cathode of the diode 10h. The anode of the diode 10h is grounded. The cathode of the diode 10g is connected to one electrode of the capacitor 10i. The other electrode of the capacitor 10i is grounded.
[0020]
The diodes 10g and 10h and the capacitor 10i form a rectifier circuit. A connection point between the anode of the diode 10g and the capacitor 10i is connected to one end of the resistor 10j, and one electrode of the smoothing capacitor 10k is connected to the other terminal of the resistor 10j. The other electrode of the smoothing capacitor 10k is grounded. A connection point between one electrode of the capacitor 10k and the resistor 10j becomes an output terminal OUT of the S meter 10, and a voltage corresponding to the average power of the received signal is charged in the smoothing capacitor 10k. For example, when a DC ammeter 10m is connected between the output terminal and the ground, the measured value of the average power can be read.
[0021]
The state detection unit 11 is connected to the output terminal of the S meter 10 and is also connected to the frame synchronization unit 3. The state detection unit 11 detects a state where the level of the received signal is equal to or higher than a predetermined value and frame synchronization is not established.
[0022]
Hereinafter, the operation of the communication apparatus in FIG. 1 will be described with reference to FIGS. 3 and 4.
FIG. 3 is an explanatory diagram of the digital data group DT transmitted from the transmission side. FIG. 4 is a timing chart showing the operation of FIG.
The communication device T on the transmission side encodes an analog audio signal to be transmitted, divides it into a plurality of audio frames (audio) 21, and forms a digital data group DT as shown in FIG. In the digital data group DT, header information 22, a burst signal (frame synchronization) 23 for establishing frame synchronization, and a burst signal (bit synchronization) 24 for establishing bit synchronization are added before the audio frame 21. Has been. The communication device T on the transmission side modulates a carrier wave by the digital data group DT and radiates a modulated wave. In FIG. 3, the burst signal 23 is arranged at one place, but may be arbitrarily arranged between the plurality of audio frames 21.
[0023]
The communication apparatus of FIG. 1 receives the modulated wave with an antenna 1. The down converter 2a of the reception processing unit 2 converts the modulated wave input via the antenna 1 into an intermediate frequency signal, and the demodulation circuit 2b demodulates the intermediate frequency to generate a baseband signal. The bit synchronization circuit 2c establishes bit synchronization using the burst signal 24 with respect to the baseband signal. Thereby, the bit string data S2 corresponding to the digital data group DT is generated.
[0024]
The frame synchronization unit 3 searches the bit string data S2 for a place having the same bit pattern as the burst signal 23, and when the place can be searched, specifies a position corresponding to each frame. That is, frame synchronization is established. If the same bit pattern location as that of the burst signal 23 cannot be searched, that is, if frame synchronization cannot be established, the frame synchronization unit 3 continuously repeats the search for the bit string data S2 that are sequentially input.
[0025]
The audio data extraction unit 4 extracts data corresponding to each audio frame 21 in the bit string data S2 based on the position information of each frame specified by the processing of the frame synchronization unit 3, and corresponds to the audio signal that was the transmission target. Create a digital audio data sequence.
[0026]
The decoding unit 5 decodes the audio data sequence provided from the audio data extraction unit 4 and provides the decoded data to the switch 6.
On the other hand, the synthesizer 7 generates an audible sound signal that is a source of audible sound used to indicate a state in which frame synchronization is not established, and outputs the audible sound signal to the switch 6. In addition, the S meter 10 measures the average power using the output signal of the down converter 2a as a reception signal of the communication device, and gives a voltage indicating the average power to the state detection unit 11.
[0027]
The state detection unit 11 detects the current state from the voltage provided from the S meter 10 and the processing result of the frame synchronization unit 3. That is, the state detection unit 11 includes a state where the level of the received signal is equal to or higher than a predetermined value and frame synchronization is not established, a state where the level of the received signal is equal to or higher than a predetermined value and frame synchronization is established, A state where the level is less than a predetermined value and frame synchronization is not established and a state where the level of the received signal is less than a predetermined value and frame synchronization is established are detected, and a corresponding switching signal is given to the switch 6 .
[0028]
When the state detection unit 11 detects that the level of the received signal is less than the predetermined value and the frame synchronization is not established, the state detection unit 11 outputs a switching signal that does not cause the switch 6 to output a signal. .
[0029]
When the state detection unit 11 detects that the level of the received signal is equal to or higher than the predetermined value and the frame synchronization is not established, the state detection unit 11 selects the output signal of the synthesizer 7 for the switch 6. A switching signal for outputting is output.
[0030]
When the state at that time is detected that the level of the received signal is equal to or higher than the predetermined value and the frame synchronization is established, the state detection unit 11 selects the output signal of the decoding unit 5 for the switch 6. The switch signal to be output is output.
When the state detection unit 11 detects that the level of the received signal is less than the predetermined value and the frame synchronization is established, the state detection unit 11 outputs a switching signal that does not cause the switch 6 to output a signal. When the state detection unit 11 detects each state, it confirms for a certain time that the received signal has become greater than or less than a predetermined value, and determines whether or not frame synchronization has been established for a certain time to determine the state. The reliability of state detection is improved.
[0031]
The switch 6 operates according to the switching signal output from the state detection unit 11. The amplifier 8 amplifies the signal given from the switch 6 and gives it to the speaker 9.
As a result, for example, during a period in which the digital data group DT is not transmitted from the communication device T on the transmission side, the output of the S meter 10 is less than a predetermined value as shown in FIG. Also, frame synchronization is not established. Therefore, the speaker 9 does not generate sound.
[0032]
When the digital data group DT is transmitted from the transmitter T, the level of the output signal of the down converter 2a increases and the reception processing unit 2 outputs the bit string data S2. Here, when the frame synchronization is not established, the switch 6 outputs the output signal of the synthesizer 7, so that the speaker 9 generates a predetermined audible sound (beep sound or the like). Frame synchronization is not established due to the influence of fading and the like, and there are cases where analog waves or digital waves having different frame configurations exist in the communication channel. The user can recognize that he / she is receiving, although he / she can only hear and not hear the sound.
[0033]
When the digital data group DT transmitted from the communication device T is finished while the speaker 9 is generating a predetermined audible sound, the level of the output signal of the S meter 10 is lowered, so that the switch 6 is the source of the sound. No signal is output. Therefore, the speaker 9 does not generate sound. Thereby, the user can recognize that the communication has ended.
[0034]
Further, when the digital data group DT is transmitted from the transmitter T and frame synchronization is established, the switch 6 outputs the output signal of the decoding unit 5, so that the speaker 9 corresponds to the decoded audio signal. Generate sound.
[0035]
When the digital data group DT transmitted from the communication device T is finished while the speaker 9 is generating sound, the level of the output signal of the S meter 10 decreases to become less than a predetermined value, and the bit string data S2 Is not output from the reception processing unit 2. At this time, the switch 6 does not output a signal that is a source of sound. Therefore, the speaker 9 does not generate sound. Thereby, the user can recognize that the communication has ended.
[0036]
As described above, the communication apparatus according to the present embodiment can reproduce the audio signal to be transmitted, and can perform predetermined allowance during a period in which the frame synchronization is not achieved and the sound is silent even if the received signal level is equal to or higher than the predetermined value. Listening sound can be generated. Therefore, the usability of the communication device is improved.
[0037]
[Second Embodiment]
FIG. 5 is a block diagram showing a communication apparatus according to the second embodiment of the present invention.
This communication apparatus includes an antenna 31, a reception processing unit 32, a frame synchronization unit 33, an audio data extraction unit 34, an S meter 35, a CPU 36, a memory 37, a state detection unit 38, and a decoding unit 39. And an amplifier 40 and a speaker 41.
[0038]
A reception processing unit 32 is connected to the antenna 31, and a frame synchronization unit 33, an audio data extraction unit 34, and an S meter 35 are connected to the reception processing unit 32. The antenna 31, the reception processing unit 32, the frame synchronization unit 33, the audio data extraction unit 34, and the S meter 35 are the antenna 1, the reception processing unit 2, the frame synchronization unit 3, and the audio data extraction unit 4 of the first embodiment. And the S meter 10.
[0039]
In the communication apparatus of FIG. 5, a CPU 36 is connected to the output side of the audio data extraction unit 34. A memory 37 is connected to the CPU 36.
The CPU 36 is provided in place of the switch 6 of the first embodiment, and the memory 37 is provided in place of the synthesizer 7. The memory 37 stores digital data to be audible sound.
[0040]
A state detector 38 is connected to the output side of the S meter 35. The state detection unit 38 has the same function as the state detection unit 11 of the first embodiment, and the output terminal of the state detection unit 38 is connected to the CPU 36.
[0041]
A decoding unit 39 is connected to the output side of the CPU 36, and an amplifier 40 and a speaker 41 are sequentially connected to the output side of the decoding unit 39. The decrypting unit 39 decrypts the digital data output from the CPU 36. The amplifier 40 and the speaker 41 are the same as the amplifier 8 and the speaker 9 of the first embodiment.
[0042]
Next, the operation of this communication apparatus will be described.
For the digital data group DT transmitted from the communication device T on the transmission side (not shown) as in the first embodiment, the antenna 31, the reception processing unit 32, the frame synchronization unit 33, and the audio data extraction unit 34 It operates in the same manner as the antenna 1, the reception processing unit 2, the frame synchronization unit 3, and the audio data extraction unit 4 of the embodiment, and digital audio data is given to the CPU 36 from the audio data extraction unit 34. The S meter 35 detects the level of the received signal and gives it to the state detector 38.
[0043]
Similarly to the state detection unit 11 of the first embodiment, the state detection unit 38 has a predetermined level of the reception signal based on the level of the reception signal given from the S meter 35 and the processing result of the frame synchronization unit 33. More than the value and frame synchronization is not established, the received signal level is greater than or equal to a predetermined value and frame synchronization is established, and the received signal level is less than the predetermined value and frame synchronization is not established A state and a state where the level of the received signal is less than a predetermined value and frame synchronization is established are detected. The S meter 35 indicates the detection result state to the CPU 36.
[0044]
When the state at that time is a state where the level of the received signal is less than the predetermined value and frame synchronization is not established, the CPU 36 outputs nothing. When the state at that time is a state where the level of the received signal is equal to or higher than a predetermined value and frame synchronization is not established, the CPU 36 outputs audible sound data read from the memory.
[0045]
When the state at that time is a state in which the level of the received signal is equal to or higher than a predetermined value and frame synchronization is established, the CPU 36 outputs the audio data provided from the audio data extraction unit 34. When the state at that time is a state where the level of the received signal is less than a predetermined value and frame synchronization is established, the CPU 36 outputs nothing.
[0046]
The decoding unit 39 decodes the data output from the CPU 36 and provides the data to the amplifier 40. The amplifier 40 amplifies the signal given from the decoding unit 39, and the speaker 41 generates sound corresponding to the signal given from the amplifier 40.
[0047]
By performing such an operation, when frame synchronization is not established when the digital data group DT is transmitted from the transmitter T, the CPU 36 outputs the audible sound data read from the memory 37. The speaker 41 generates a predetermined audible sound. Frame synchronization is not established due to the influence of fading and the like, and there are cases where analog waves or digital waves having different frame configurations exist in the communication channel. Even in such a case, the user can recognize that he / she is receiving, although he / she is only hearing and no sound is heard.
[0048]
When the digital data group DT transmitted from the communication device T ends when the speaker 41 generates a predetermined audible sound, the level of the output signal of the S meter 35 becomes less than a predetermined value. At this time, the speaker 41 does not generate sound. Thereby, the user can recognize that the communication has ended.
[0049]
Further, when the digital data group DT is transmitted from the transmitter T and frame synchronization is established, the CPU 36 outputs the audio data output from the audio data extraction unit 34, so that the speaker 41 converts the decoded audio signal into the decoded audio signal. Generate the corresponding sound. When the digital data group DT transmitted from the communication device T is finished while the speaker 41 is generating sound, the level of the output signal of the S meter 35 becomes less than a predetermined value. At this time, the speaker 41 does not generate sound. Thereby, the user can recognize that the communication has ended.
[0050]
As described above, in the communication device of this embodiment, as in the first embodiment, it is easy to use and the memory 37 stores audible sound data, so that the audible sound can be easily changed. Have
[0051]
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. Examples of such modifications are as follows.
(1) In the first and second embodiments, the communication device T wirelessly transmits the digital data group DT. However, the present invention can also be applied when the communication device T transmits by wire.
[0052]
(2) In the second embodiment, the CPU 36 may have the function of the state detection unit 38, and the state detection unit 38 may be omitted.
(3) The present invention is applicable not only to reception and reproduction of audio data but also to packet communication of other data.
[0053]
【The invention's effect】
As described above in detail, according to the present invention, an easy-to-use communication device can be realized.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a communication apparatus according to a first embodiment of the present invention.
FIG. 2 is a circuit diagram showing a configuration example of an S meter in FIG.
FIG. 3 is an explanatory diagram of a digital data group DT transmitted by a communication device T.
4 is a timing chart showing the operation of the communication apparatus of FIG. 1. FIG.
FIG. 5 is a configuration diagram showing a communication apparatus according to a second embodiment of the present invention.
[Explanation of symbols]
1, 31 Antenna 2, 32 Reception processing unit 3, 33 Frame synchronization unit 4, 34 Audio data extraction unit 5, 39 Decoding unit 6 Switch 7 Synthesizer 9, 41 Speaker 10, 35 S meter 11, 38 State detection unit 36 CPU
37 memory

Claims (3)

Receiving means (2, 32) for receiving a digital data group in which a signal to be transmitted is encoded by the transmission side and dispersed and incorporated into a plurality of frames;
Synchronization establishment means (3, 4, 33, 34) for establishing frame synchronization for the digital data group received by the reception means (2, 32) and detecting each frame;
Restoring means (5, 39) for restoring the transmission target signal based on the processing result of the synchronization establishing means (3, 4, 33, 34);
Level measuring means (10, 35) for measuring the level of a signal received by the receiving means;
State detecting means (11, 38) for detecting a state in which the level of the signal received by the receiving means is equal to or higher than a predetermined value and the frame synchronization is not established based on the measurement result of the level measuring means;
Audible sound generating means (6, 7, 8) for generating a predetermined audible sound when the state detecting means (11, 38) detects that the level is not less than a predetermined value and the frame synchronization is not established. , includes a 9,36,40,41), the,
The transmission target signal is an audio signal,
Based on the measurement result of the level measuring means (10, 35), the state detecting means (11, 38) is such that the level of the signal received by the receiving means (2, 32) is not less than a predetermined value and the frame synchronization is A first state that is not established; a second state in which the level of the signal is equal to or greater than a predetermined value and the frame synchronization is established; and a level of the signal is less than a predetermined value and the frame synchronization is established. Detecting a third state that is not present and a fourth state in which the level of the signal is less than a predetermined value and the frame synchronization is established;
The audible sound generating means (6, 7, 8, 9, 36, 40, 41) generates the predetermined audible sound when the first state is detected, and the second state is detected. A communication device that generates sound corresponding to the sound signal restored by the restoration means, and does not generate sound when the third state or the fourth state is detected. The communication apparatus according to claim 1, wherein the digital data group is transmitted wirelessly from the transmission side.   The transmission side signal of the audio signal is encoded by the transmission side and is received in a digital data group dispersed and incorporated into a plurality of frames, frame synchronization is established for the digital data group, and each frame is detected. A communication method for restoring the transmission target signal based on a result,
  A first state in which the level of the received signal is measured, the level is not less than a predetermined value and the frame synchronization is not established, and a second state in which the level is not less than a predetermined value and the frame synchronization is established. Detecting a state, a third state in which the level is less than a predetermined value and the frame synchronization is not established, and a fourth state in which the level is less than a predetermined value and the frame synchronization is established;
  A predetermined audible sound is generated when the first state is detected, a sound corresponding to the restored transmission target signal is generated when the second state is detected, and the third state or A communication method characterized in that no sound is generated when the fourth state is detected.

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