JPS6153835A - Radio communication device - Google Patents

Abstract

PURPOSE:To make no response to electric field variation during a high-speed run and suppress a noise at the time of on-hook operation by providing a control circuit which receives the output of an on-hook signal detecting means and the output of a received electric field detecting means and controls squelch operation. CONSTITUTION:The digital mobile radio communication device sends an on-hook signal composed of a specific digital data sequence at the end of transmission and then turns off a transmission output. A receiver when detecting the arrival of a received radio wave by a receiving level detector 13 inputs detection voltage Vs to a comparing circuit 17. The circuit 17 compares the voltage Vs with a reference voltage Vref and outputs a control signal (e) of 0 when Vres>Vs or 1 when Vref<Vs to a control circuit 19. An on-hook signal detecting circuit 18 when detecting the on-hook signal outputs a pulse (f) to the circuit 19. The circuit 19 inverts a squelch control signal (g) to 0 when the signal (e) is 0 and turns off squelch operation for an audio amplifier 14. When the signal (f) is generated, or when the signal (e) is at a level 1, the circuit 19 rises the signal (g) to 1 to perform the squelch operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a wireless communication device such as a digital mobile radio that transmits voice and digital data using a wireless transmission path.

The configuration of a conventional example and its problems FIG. 1 shows a diagram of a digital mobile radio system. In Fig. 1, 1 (↑) is an encoder, and the encoder 1 converts an analog input signal (i'') such as voice into a digital signal. ;゛]lc
-J, 1-t)' signal is modulated. This ☆ tone (
The bow is sent out as a radio wave via a) Sui a:%3.

- radio wave 1.1 '3 (,'', received by instrument 4e, 1st modulator 5' (IIi!, after modulated lJ,
With Yakugi 6, Anna [] is the 1' L of the plague, and it's a bit of a bit of a bit!・
It is output via amplifier 7.

Here, the shape 11ij of the non-rAIiil line can be grasped, and the input lightning Z intensity / + . (Ding!
The Shinden W detector 8 has a frequency discriminator output band 11.
11γ′lI+! Min & Φj11 detection t) so 1-
), or I-) which detects the intermediate frequency amplitude may be used.

Reception level detector: Number of 8; I II', comparison circuit 9
In addition, λI), the input electric field is determined to be low F by 311 times smaller than the reference value \/rer set by the bT variable resistor 10121-1, and the fame amplifier 7 is set to 0. Make it E.

This, 1, 5'! T17 (Future wireless communication device i'''
1, the detection 11'1 constant of the electric field detector 8 is ylo
If you do so, the fading that occurs when driving at high speeds ,
) Since electric field fluctuations are detected and the audio amplifier 7 is frequently disconnected and disconnected, it is very audible and the sound is loud and loud. Is the above detection time fixed because of A? JI l: 1, compared to fading Shumei, it is necessary to keep it to a certain extent. For example, 150M Ll 7 band movement;! ! (Line) In the case of Iku, the fading lap when traveling at 40 km/h is 1111! Since i, 5l-1z, it is normal to set the detection n;lr constant to 100-200m5ec.

-1+, If you set the time constant like this, when the other party's wireless device finishes talking 110 times and stops transmitting, 1:...
Receive(, -i till's slube detection is not performed promptly, so the period is 100-200+n5ec ti
Glume? 'S' is output. That is, at present, there is a drawback that noise is output from the speaker of the receiving radio device at the corner where the other party's radio device ends the call, resulting in a very loud noise.

Purpose of the invention Mizumoto Akiban 51 Reacts to electric field fluctuations due to fading when running at high speed 1! First, it is an object of the present invention to provide a wireless communication device capable of suppressing noise at the end of a call by promptly detecting the end of a call and operating Snow Norge.

Structure of the Invention The communication device of the present invention includes a transmission (ti i control means) that cuts off the transmission after transmitting a termination signal consisting of a specific digital data string at the end of transmission, and a reception control means. At the same time, the call-end signal detection means detects the call-end signal, the reception electric field detection means detects the arrival of the received radio waves, and the output of the call-end signal detection means and the output horn of the reception electric field detection means are used as input data to perform a squelp operation. A control circuit for controlling the received electric field detection circuit is provided, and this control circuit is connected to the received electric field detection circuit.
'rti h! The arrival of l is detected and the squelp operation is performed at iJ, and the end call signal detecting means detects the end of the call, l, 2l +, 'l 4) 17 < l mama 1! -C'J to received phone W detection Tf9 (ii electric du 17) +1
! i Loss detection 1/, :II> 1. : S'T Ruchi It Sakui Δn, \! ! Ro, 1. U (quality 1, 2 (2nd is special 1st grade).

If you want to end the call, immediately cut off the transmission output and add 8 to 11. Send the signal and send the final message to the receiving side 1c'): "% Shift 1 ~ Send later (,'i
Notify the user of the end of the conversation 1).
1) Therefore, it is possible to suppress the generation of noise caused by 114 due to disconnection of the receiving input, and to perform smooth communication.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will now be described with reference to FIGS. 2 to 4.

FIG. 2 shows the configuration of a receiver in the wireless communication device of the present invention. Reference numeral 011 is a receiver that amplifies the received input, converts the frequency to an intermediate frequency, amplifies the intermediate frequency signal, and limits the amplitude. The output η is outputted to the modulator 12 with a constant amplitude of −5=interval frequency. 1 in adjuster 12′);L
13 is a decoder; 13 is a decoder; ΔM, I]C
M115 and its modified code are output as 1 (original modulation manual and 1111 analog r3) to the original signal 8.14
is an audio signal amplifier, and the analog tF3 from the decoder 13
When '14 is amplified, output to speakers etc. is 0N10[1: according to the squelp control signal. i ht,
is a reception level detector, which detects the intermediate frequency and outputs it through the IL DC electric port Vs so as to be proportional to the decibel value of the reception input level, and the receiver 11 has a reception level display. When an integrated circuit is used, it is sufficient to receive the output of the level display voltage at the 14 output signal of the novel detector 15. Reference numeral 16 denotes a generator for generating the base voltage V ref of the filter, which is based on the reception level i4 at which squelch is applied by dividing the voltage of the stabilized power supply at 1 V. Reference numeral 17 denotes a voltage comparison circuit which compares the output voltage of the reception level detector 15 with the reference voltage V ref and, if V ref > VS, returns IQ II.

When Vref<Vs, (r I 11 is used as a control signal e and output = 6 -. Note that depending on the integrated circuit for intermediate frequency amplification in receiver A8 11, when there is no reception input, the reception level detector In some cases, the input voltage to 15 is the maximum, and this voltage decreases as the received input increases.

In this case, 1i1); For L Qu space TIVref, if Vref<Vs, “(1”, Vref>
In the case of vs, G: outputs "1" as DII Jinshi] (]). Here, we will explain the former case as an example. 18 is the end of the story (1 'T Fj
Ending the conversation 1) Detecting that 1) has been output to the controller 12.
When the i9 detection circuit detects a call end signal, it outputs a pulse liE.
F3f wo l'F cow. 19 t;L iti'l
111 circuit detects the vI tri-1 of Hals Buddha R, changes the squelch control signal 0 from "1" to "0" λ, turns the acoustic amplifier 14 from ON to OFF, and also compares the loss of received radio waves. 17 is detected and the control signal @e becomes 0'', the squelch control signal 0 is changed to 0'', and after the -th squelch control signal 0 reaches 0゛'t, the received radio wave arrives. The squelch control signal 0 is set to 1'' only when the comparator v811 detects this and the control signal e becomes 1''.

Next, an example of the end-of-call signal will be explained with reference to FIG.

PT is the transmission output, Psw is the breath talk switch output,
D represents a digital data signal, and E represents a call termination signal. When you end a call and turn off the breath talk switch, the breath talk switch output Psw changes from "1" to 0.
However, the transmission output is kept in the ON state until the transmission output 1) Tt is completed. The transmission of the end-of-call signal is 1 frame per norm, but whether it is sent over several frames depends on the radio frequency used and the type of mobile station, such as a car,
The number of frames required for IRR is set depending on whether it is for a train, an aircraft, or a portable device. However, if it is possible to detect the speed and direction of travel like a car, it is not possible to change the speed and direction of the vehicle by adjusting the tenth bar A'1. In FIG. 3, the horizontal axis represents time t, and the vertical axis represents signal 0N10[-[ or level.

Now, at point A, press switch 1) and switch 6 to OFF.
The following describes the situation. The digital data signal is transmitted at 101<bit/sec, with an 8-bit frame synchronization signal attached every 32n+s, and one frame is 32 bits per second.
(lb port. Of these, 312 bits are data bits 1~.The end of call signal detection circuit 18 detects the frame synchronization signal t
, 1, and starts reception by incrementing 6 bits 1- by 1 from the next bit of the frame synchronization signal.

In this operation, both the audio data before point A and the 312 bits immediately after the frame synchronization signal are always received. One frame of the end-of-call signal E consists of an 8-bit frame synchronization signal and 39 pieces of 8-bit end-of-talk data, and each 81+it represents "0" or "1". The first 1) i[ is necessarily ゛“0
``Do<'K ・)''C (This is Pa1''Doshite OJ
-b). Adaptive delta modulation (△dapNve 8M) 1
Kooi C is ' 1 ") l is 0" is - 1 [gotsuto or more consecutive 1) r, occurrence () (J), it is known that the decoded output will be almost silent, so end the story. signal 8bit
Each 81) x 39 pieces of 1st data are arranged in a pip[・configuration and 1) like 1. Immediately J), data “0′° is '0101
0i o i” 8 pin 1-, data “1” is “00”
The 8 pitches 1~ of 101010'' are constructed, and the subsequent 2~8 pitches h excluding the first hit are complementary, and the two parts are ORed through 1~ and J'' and continuous ``1''. Data “0”
In Onibi 1'', data ``1'' becomes O and data ``0'' becomes 1 in the majority decision using 2 to 8 bits (7 bits). Of course, this means that data and a large number of bonds correspond to data "1" to 1 and data "0" to O 1! It's okay.

What is important about this bit string is that the end-of-call signal F must not give unnecessary noise in adaptive delta modulation, as described above. The above 39 data are not necessarily "' 1010
Since we are giving a specific pattern that is guaranteed by the system, rather than a ``1'' pattern, we are giving a pattern that does not result in a ``1'' or ``0'' above the ``4'' for each data combination. °' or "1". G reduces the data string for each data combination by
It is known that 11 or higher will not occur. The 39 data signals of the end call signal ¥3 are composed of BC11 codes or Hagelberger codes, each of which performs ff1i+positive.

The 8-bit data following the frame synchronization signal is -10
= When it is imported into temporary memory, it occurs in the first bit of each of the 39 pieces of data (NO31 bit to 8 bits 1).
The number 011 is 4 (), and the number of '0°' is m or more (
For example, a+ = 30), if the frame is a final sign, the data pattern of the frame 11 is verified (determined to be false, then the next) l norm Continue testing for

When it is determined that the received signal is a call-end signal, the call-end signal detection circuit 18 sends a control signal @f to the control circuit 19.

FIG. 4 is a flowchart of the end of call determination process in the end of call r:3 detection circuit 18, which is performed for each frame.

(Step 1) → Verify the first bit of the 8-pi 1-tortoise following the frame synchronization Shingetsu and execute [Step 2].

Count the number of (Suj Tsubu 2)→゛0゛'' and determine that the number no is no>m <for example...-30), and n.

≦Il+speed 1; 1 Return to the start, and execute (step 3) for rlO>II and 2λ.

3) Execute the error correction iT for 171 nodes at the 0th order.

(Step 4) → Read the received data from the temporary memory, check whether it is a call end signal or not, return to star if no, and if YES, judge it as the end of the call and use it as the subsequent The control circuit 19 is notified of the end of the conversation.

That is, the receiver shown in FIG. 2 turns on the audio amplifier 14 when a radio wave arrives, and turns off the audio amplifier 14 when a call termination signal is detected or when the radio waves are cut off at 4T.

Closing signal 8 [; Ai, when I signaled it, it was already (J who said this:
Since the end of the call is almost silent, as long as the call is ended by the end of call signal, the It sound will not be emitted when the call is ended. Only when the quality of the wireless line rapidly deteriorates due to fading etc. and a call-end signal cannot be detected, the call is terminated by detecting a radio wave interruption, so noise occurs when the call ends, but the call-end signal is sent. The frequency of this occurrence can be reduced by measures such as increasing the number of frames. In addition, the demodulation output at the receiver [19 signal 13 output] of the end call signal transmitted from the transmitter is sufficiently low compared to the demodulation output level of the normal signal p3. By using a signal with a frequency component outside the reception demodulation band, the user of the reception (A 1111) will no longer be able to hear the end-of-call signal, improving the usability.

31 of the explanation of Song Yi-I, the wireless communication device of the present invention includes a transmission control means that turns off the transmission output after transmitting a termination signal consisting of a specific digital data string at the end of transmission, and a A squelch operation is performed using the end of call signal detection means for detecting the end of call signal, the received electric field detection means for detecting the arrival of the receiving radio wave, and the output of the end of call signal detection means and the output of the received electric field detection means as input data. a control circuit for controlling il+, the control circuit turns off the squelch operation when the received electric field detecting means detects the arrival of a received radio wave, and when the end of call signal detection means detects the end of call signal. Alternatively, since the received electric field detection means is configured to turn off the squelch operation when the loss of received radio waves is detected, the end of the call can be quickly detected even if the detection time constant of the electric field detection means is longer than the fading period to some extent. What you can do is reduce the noise at the end of a call (
By completely suppressing this problem, it is possible to achieve smooth communication.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional digital mobile radio communication device, Fig. 2 is a block diagram of an embodiment of the receiving section in the radio communication device of the present invention, and Fig. 3 is a call termination signal transmitted from the transmitter side. FIG. 4 shows a flowchart for verifying the end-of-call signal in FIG. 2.

Claims (1)

[Scope of Claims] 1. Transmission control means that turns off transmission output after transmitting a call end signal consisting of a specific digital data string at the end of transmission, and call end signal detection means that detects the call end signal upon reception. and a receiving electric field detecting means for detecting the arrival of received radio waves, and a control circuit for controlling a squelch operation using the output of the end-of-call signal detecting means and the output of the receiving electric field detecting means as input data. The squelch operation is turned off when the reception electric field detection means detects the arrival of the reception radio wave, and when the call termination signal detection means detects the termination signal or the reception electric field detection means detects the disappearance of the reception radio wave. A wireless communication device configured to turn on squelch operation at certain times. 2. The end-of-call signal sent from the transmitter is a signal whose demodulated output level at the receiver is sufficiently lower than the demodulated output level of the normal signal, or a signal whose frequency component is outside the reception demodulation band. A wireless communication device according to claim 1.