JPH11346164A - Receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiver in which the improvement of real use operation of an audio gap including absorption of a pop noise can be performed. SOLUTION: This device is a PLL system receiver equipped with an electronic volume 8 for adjusting volume, a muting part 4 for performing operation of muting/unmuting an output of the electronic volume 8, and a control means 7 for controlling the electronic volume 8 and the muting part 4. When the operation of the muting part 4 changes from mute to unmute, the control means 7 controls the electronic volume 8 so that its output level changes stepwise from zero to the level at muting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a receiver.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing an example of a conventional receiver. The receiver in FIG. 5 is, for example, a PLL business radio receiver with a priority scan function, and 1 is an antenna, 2 is a receiving unit, 3 is a PLL (phase locked loop) unit, 4 is a muting unit, Reference numeral 5 denotes an audio amplifier unit, 6 denotes a speaker, and 7 denotes a microprocessor. The microprocessor 7
Each operation of the PLL unit 3 and the muting unit 4 is controlled.

[0005] In the receiver shown in FIG. 5, during scanning, even when receiving data on a normal CH (channel), the priority channel (Priority C) is transmitted at regular intervals.
H) to watch. The period of this watch (several hundred
During milliseconds, the conversation (received sound) of the normal CH is interrupted, and a period during which the received sound is interrupted is called an audio gap.

FIG. 6 is a waveform diagram of a received signal for explaining an audio gap. As shown in FIG. 6, the received sound being received on a certain normal CH is interrupted during the watch period of the priority CH to generate an audio gap, and thereafter the reception is switched from the priority CH to the reception on the normal CH again to obtain the reception sound.

[0005] As described above, when switching from the priority CH to the reception on the normal CH again, the frequency is stabilized, so-called PLL.
During the period until the unit 3 is stabilized, the detection output in the receiving unit 2 fluctuates, and the received sound becomes uneven as shown in FIG. Therefore, under the control of the microprocessor 7, the muting section 4 is controlled to be muted until the PLL section 3 is stabilized, so that pop noise cannot be heard from the speaker 6. The microprocessor 7 controls the operation of the muting unit 4 to change from mute to unmute so that the received sound can be heard from the speaker 6.

[0006]

However, if a stable detection output is obtained by setting the audio gap to be longer, pop noise can be suppressed, but there is a possibility that the user may recognize interruption of the received sound. is there. Therefore, the shorter the audio gap, the better. However, since the receiving channel is switched, if the operation of the muting unit 4 is changed from mute to unmute before the PLL unit 3 is stabilized, pop noise may be heard from the speaker 6. As described above, in the conventional receiver configuration, the audio gap becomes longer when a stable detection output is waited, and pop noise becomes conspicuous when unmute is performed early.

An object of the present invention is to provide a receiver which has solved the above-mentioned problems.

[0008]

SUMMARY OF THE INVENTION A receiver according to the present invention comprises:
An electronic volume for adjusting a volume, a muting unit for performing an operation of muting / unmuting an output of the electronic volume, and a control unit for controlling the electronic volume and the muting unit, as described in claim 1. Wherein the control means gradually changes the output level of the electronic volume from zero to a mute level when the operation of the muting section changes from mute to unmute. It is characterized in that it is controlled to change.

[0009]

FIG. 1 is a block diagram showing an embodiment of a receiver according to the present invention. The receiver of FIG.
Is a PLL system business radio receiver with a priority scan function as in the conventional example shown in FIG.
Is a PLL section, 4 is a muting section, 5 is an audio amplifier section, 6 is a speaker, 7 is a microprocessor, 8 is an electronic volume (VR), 9 is a volume switch (SW).
It is.

The microprocessor 7 controls the operations of the PLL unit 3, the muting unit 4, and the electronic VR 8. A method of adjusting the volume of the electronic VR 8 is as follows. A variable voltage from a volume switch (mechanical SW) 9 composed of a variable resistor connected between the voltage source VDD and the ground
The microprocessor 7 controls the electronic VR 8 based on the voltage value and determines the volume level. The reason why the volume level is once taken into the microprocessor 7 is that there is a function of keeping the volume level constant regardless of the variable position of the volume SW 9.

A feature of the present invention is that the microprocessor 7 controls the mute / unmute operation of the muting section 4 and the volume adjustment operation of the electronic VR 8 in combination with the mute / unmute operation during the priority scan in the configuration of FIG. , Mute is released (unmuted) early while reducing pop noise. When the muting section 4 is unmuted, the microprocessor 7 can open the mute as soon as possible while absorbing pop noise by opening the volume of the electronic VR 8 stepwise instead of opening it all at once.

That is, while receiving the normal CH, the electronic VR8
Is adjusted to a predetermined volume level so that the variable volume obtained by switching the volume SW 9 by the user is supplied to the microprocessor 7 so that the volume can be heard from the speaker 6 at an appropriate volume. Next, during the priority scan, at the beginning of the audio gap period, the microprocessor 7
Controls the muting section 4 to perform a mute operation so that noise from the speaker 6 cannot be heard.

Next, at the end of the audio gap, the microprocessor 7 controls the muting section 4 to perform an unmute operation, and at the same time, controls the electronic VR.
8 is controlled so as to change stepwise from zero to the predetermined volume level. Thereafter, by the time the detection output of the receiving unit 2 is stabilized, the electronic VR 8 has returned to the predetermined volume level and the muting unit 4 has been unmuted. You can hear the received sound at the volume.

FIG. 2 is an example of the volume output level characteristic of the electronic VR 8, and shows a state in which the target value (original volume level) is gradually increased from level zero. Electronic VR8
Specifically, the time during which the volume output level is varied stepwise is about 15 milliseconds, and the volume level is changed every 2.5 milliseconds by dividing the 15 milliseconds into six.
The step change of the electronic VR 8 for 15 milliseconds starts from the level zero at the start of the turbulence in FIG. 6 and overlaps for 5 s after the 10 msec required for stabilization of the PLL unit 3 (no turbulence). It has become.
The variable value of the volume output level of the electronic VR 8 is determined by multiplying the volume level to be actually output × table data (stored in the internal memory of the microprocessor 7 in advance). This table data is
For example, there are six data of 0.1, 0.2, 0.3, 0.4.1, and 1, as shown in FIG. Stored in memory. Since the value of the table data is 1 or less, the multiplied value is smaller than the original volume level.

Next, a method for changing the volume output level of the electronic VR 8 stepwise will be described with reference to a flowchart shown in FIG. First, in step S1, it is determined whether or not the internal counter of the microprocessor 7 is 1. If no, the process proceeds to S2, where the calculation of volume level × table data = D / A volume level out is performed.
At 3, the counter value is decremented by 1 and then S1
Then, the same operation is performed, and the operation is terminated when the counter is determined to be 1 in S1.

Therefore, by the operations of steps S1 to S3, first, the multiplied value obtained by multiplying the original volume level by the table data "0.1" corresponding to the counter value "6" is obtained after the D / A conversion of the electronic VR8. A volume output level is obtained, and then a multiplied value obtained by multiplying the original volume level by the table data “0.2” corresponding to the counter value “5” becomes a volume output level after D / A conversion of the electronic VR 8. Similarly, finally, the multiplied value obtained by multiplying the original volume level by the table data “1” corresponding to the counter value “1” becomes the volume output level after D / A conversion of the electronic VR 8, and as a result, Overall, the volume output level of the electronic VR 8 changes stepwise.

The curves of the stages can be set by the program software of the microprocessor 7, and by changing the number of counter values and the contents of the table data,
Linear wind, exponential wind, logarithmic wind, original, etc. can be set freely. The function of the wireless device can be set by using personal computer software. Similarly, the value of the electronic VR can be changed by using the personal computer software.

As described above, the priority scan function normally uses the CH
Even if the PLL circuit remains violent during reception, pop noise can be absorbed without significantly sacrificing the audio gap time, and the actual operation of the audio gap including the absorption of pop noise can be improved.

[0019]

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made. For example, a signal passing through the electronic VR can be applied to any of the following. (1) It can be used not only during priority scanning but also when changing channels. (2) It is possible not only at the time of unmute but also at the time of mute step by step. (3) The present invention can be applied to a transmission modulation system. (4) The reduction in pop noise is effective not only for the speaker user but also for the earphone user.

[0020]

According to the present invention, the actual operation of the audio gap including the pop noise absorption can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a receiver according to the present invention.

FIG. 2 shows an example of a volume output level characteristic of the electronic VR in FIG.

FIG. 3 is a diagram showing table data values corresponding to internal counter values of the microprocessor in FIG. 1;

FIG. 4 is a flowchart illustrating a volume output level calculation process of the electronic VR in FIG. 1;

FIG. 5 is a block diagram illustrating an example of a conventional receiver.

FIG. 6 is a reception signal waveform diagram for explaining an audio gap.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 Receiving part 3 PLL part 4 Muting part 5 Audio amplifier part 6 Speaker 7 Microprocessor 8 Electronic volume (VR) 9 Volume switch (SW)

Claims (1)

[Claims] 1. A PLL comprising: an electronic volume for adjusting a volume; a muting unit for performing an operation of muting / unmuting an output of the electronic volume; and a control unit for controlling the electronic volume and the muting unit. A receiver, wherein when the operation of the muting section is changed from mute to unmute, the control level of the electronic volume is changed stepwise from zero to a level at the time of mute. A receiver characterized by controlling.