JPH0578046U - Audio equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] Even if there is a time delay in the processing of audio signals by the DSP circuit 3, the shock noise at the time of tuning the PLL electronic tuner 1 is muted by the audio mute circuit provided in the preceding stage of the DSP circuit 3. Output is cut off. [Configuration] PLL electronic tuner 1 for receiving a broadcast signal,
An audio mute circuit 2 that operates when the PLL electronic tuner 1 is selected, and a DSP circuit 3 that processes the output signal of the audio mute circuit 2 into left and right front and rear acoustic outputs.
And the volume circuits 5 and 7 and the output amplifiers 6 and 8 provided in each channel.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an audio signal processing circuit of an audio device, and more particularly to an audio device suitable for reducing noise when selecting a PLL electronic tuner.

[0002]

[Prior art]

 2. Description of the Related Art Conventionally, many audio signal processing circuits for audio equipment have been provided in the block diagram shown in FIG. In the figure, reference numeral 1 is a PLL electronic tuner as a signal source, and an output signal of the PLL electronic tuner 1 is supplied to a DSP circuit 3 and an adder 4. The left channel (Lch) front signal processed by the audio signal of the DSP circuit 3 is supplied to the Lch front audio mute circuit 11 via the adder 4, and the Lch rear signal is supplied to the L ch rear audio mute circuit 12. Supplied.

Reference numeral 5 denotes an Lch front volume circuit, and an output signal of the volume circuit 5 is output to an Lch front voice through an L channel front amplifier 6. Reference numeral 7 denotes an Lch rear volume circuit, and the output signal of this volume circuit 7 is output to the Lch rear audio through an Lch rear amplifier 8. Reference numeral 9 is the right channel (Rch) front signal of the DSP circuit 3, and 10 is the Rch rear signal. The configurations of the audio mute circuit for Rch, the volume circuit, the output amplifier, etc. are the same as those of the Lch circuit, and are therefore omitted.

In the thus configured audio equipment, the PLL electronic tuner 1 receives the broadcast signal, the DSP circuit 3 processes the audio signal, and outputs the L / Rch front and rear signals. The Lch front signal is added to the output signal of the PLL electronic tuner 1 by the adder 4 and supplied to the Lch front amplifier 6 via the audio mute circuit 11 to become the Lch front audio signal.

On the other hand, the Lch rear signal processed by the DSP circuit 3 is supplied to the Lch rear amplifier 8 via the Lch rear audio mute circuit 12 and output as the Lch rear audio signal. It Similarly, the Rch front and Rch rear signals are also supplied to an output amplifier (not shown) via an audio mute circuit (not shown) to be output as audio signals from each speaker (not shown), and L / Rch (stereo) ) Was being constructed.

[0006]

[Problems to be solved by the device]

 However, in the above-mentioned conventional audio equipment, when the PLL electronic tuner 1 selects a channel, shock noise is generated by this channel selection operation. Therefore, each L / Rch audio mute circuit 11, 12 (hereinafter, Rch audio signal). (The explanation of the circuit operation is omitted.) Was turned on to prevent the shock noise from being output to the speaker. However, the output signal that was processed by the DSP electronic circuit 3 from the PLL electronic tuner 1 was processed by reverberation sound, for example. If the delay processing of the voice signal is performed by the sound signal, the shock noise time of the PLL electronic tuner 1 is also delayed.

Therefore, the shock noise remains within the mute time of the audio mute circuits 11 and 12, and the shock noise is supplied to the output amplifiers 6 and 8 and the shock noise sound is output from the speaker.

The present invention has been made in view of the above points, and its object is to solve the drawbacks of the conventional example, to arrange the audio mute circuit in the preceding stage of the DSP circuit 3, and to use the DSP circuit 3. Even if there is a time-delayed signal for audio signal processing, it is possible to mute the shock noise at the time of tuning the PLL electronic tuner 1 with the audio mute circuit in the preceding stage to provide an audio device that is not output.

[0009]

[Means for Solving the Problems]

 The audio equipment of the present invention is a DSP circuit that processes the output signal of a PLL electronic tuner that receives a broadcast signal into left and right front and rear audio outputs, and an audio mute circuit that operates when the PLL electronic tuner is selected. In the audio equipment having the above, the output signal of the PLL electronic tuner is supplied to the audio mute circuit, and the output signal of the audio mute circuit is supplied to the DSP circuit.

[0010]

[Action]

 According to this invention, an audio mute circuit is provided before the DSP circuit that processes the output signal of the PLL electronic tuner that receives the broadcast signal into the left and right front and rear audio outputs.

As described above, by arranging the audio mute circuit in the preceding stage of the DSP circuit, the shock noise generated when tuning the PLL electronic tuner can be cut off by the ON operation of the audio mute circuit.

That is, in the reception state of the normal PLL electronic tuner, the output signal of the PLL electronic tuner is in the OFF operation state. The reception output signal is supplied to the DSP circuit via the audio mute circuit, and the L / Rch front and rear are output. The signal can be processed by voice signal and output as sound. On the other hand, when the PLL electronic tuner is tuned in, the audio mute circuit is turned on, and the shock noise generated during channel selection is muted and is not output to the DSP circuit.

By arranging the audio mute circuit in the preceding stage of the DSP circuit as described above, the unnecessary output signal, which is processed by the DSP circuit as in the conventional example, is muted within the mute time of the audio mute circuit. It can be prevented from being output without being output.

[0014]

【Example】

 An embodiment of an audio device according to the present invention will be described based on the block diagram shown in FIG. The same parts as those in the conventional example are designated by the same reference numerals and the description thereof will be omitted. In the figure, reference numeral 2 is an audio mute circuit arranged so as to be connected to the PLL electronic tuner 1. The output signal of the audio mute circuit 2 is supplied to the adder 4 and the DSP circuit 3.

Further, the adder 4 can supply the amplifier 6 through the Lch front volume circuit 5 to output the Lch front acoustic signal, and the DSP circuit 3 outputs the Lch rear output signal to the Lch rear It is supplied to the amplifier 8 via the volume circuit 7. (The output circuit for the Rch front and rear output signals 9 and 10 is omitted because it is the same as the Lch front and rear circuits.) In the audio device configured in this way, the normal PLL electronic tuner 1 receives the broadcast signal. In this case, the audio mute circuit 2 is in the OFF operation state, the received broadcast signal is processed by the DSP circuit 3 and the L / Rch front and rear signals are set by the respective volume circuits 5 and 7. Sound can be output from a speaker (not shown).

On the other hand, when the PLL electronic tuner 1 performs a tuning operation, the audio mute circuit 2 may perform a mute ON operation for a predetermined mute time in accordance with the tuning operation time of the PLL electronic tuner 1. Therefore, unnecessary signals such as shock noise generated when the PLL electronic tuner 1 is selected can be blocked.

Since the audio mute circuit 2 blocks unnecessary output signals such as shock noise of the PLL electronic tuner 1 in this way, unnecessary output signals such as shock noise are not supplied to the DSP circuit 3 It is possible to completely prevent acoustic output such as noise.

That is, as in the conventional example, after the audio signal processing of the DSP circuit 3, the unnecessary output signal such as the shock noise is output through the audio mute circuit, and the signal delay is performed by the DSP circuit 3 set to the reverberation sound processing state. It is possible to prevent problems such as being output after the mute state has been released by being released.

[0019]

[Effect of the device]

 As described above, in the audio device according to the present invention, the audio mute circuit 2 is arranged in front of the DSP circuit 3, so that the shock noise from the PLL electronic tuner 1 during the channel selection operation is completely cut off by the audio mute circuit 2. There is no sound output, and it is possible to prevent an unpleasant sound due to shock noise at the time of tuning from being output to the listener who is receiving the broadcast signal.

Moreover, it has excellent features such as a simple structure and easy implementation because it can be constructed at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an audio device according to the present invention.

FIG. 2 is a block diagram showing a conventional example.

[Explanation of symbols]

 1 PLL Electronic Tuner 2 Audio Mute Circuit 3 DSP Circuit 4 Adder 5 Lch Front Volume Circuit 6 Lch Front Amplifier 7 Lch Rear Volume Circuit 8 Lch Rear Amplifier 9 Rch Front Output Signal 10 Rch Rear Output Signal

Claims (1)

[Scope of utility model registration request] 1. A DSP circuit for signal-processing an output signal of a PLL electronic tuner for receiving a broadcast signal into left and right front and rear acoustic outputs, and an audio mute circuit operating when the PLL electronic tuner is selected. In the audio equipment, the audio equipment is configured such that an output signal of the PLL tuner is supplied to an audio mute circuit and an output signal of the audio mute circuit is supplied to the DSP circuit.