JPS6124059A - Pcm sound reproducing device - Google Patents

Abstract

PURPOSE:To transmit a reference tone signal at each significant recording section by providing a means where an amplitude corresponding to a maximum value level of a PCM sound reproducer is changed in response to the maximum level at each recording section. CONSTITUTION:A sinusoidal wave generating section 4A outputs a sinusoidal wave having a peak value corresponding to the maximum value of a sound signal of each section as timewise relation of a digital value. A prescribed multiplication coefficient is multiplied with the digital signal of the sinusoidal waveform at a multiplication circuit 44. When a switch control signal is transmitted from a memory control section 32, a switch S1 is connected to the P position, a multiplication coefficient is fed to the multiplication circuit 44 from ROM 42, 43 and a prescribed multiplication coefficient is integrated to the maximum level of the PCM sound reproducer. Thus, a digital sinusoidal waveform corresponding to the maximum level at each section is inputted to an analog converting section 5 and a reference tone signal as the analog sound is outputted externally.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a PCM audio playback device.

[Conventional technology]

In recent years, 26M audio playback devices such as compact disc players have become widely available on the market.

In addition to simply listening to the above-mentioned reproduced sound, the reproduced sound is often recorded on tape. There are two types of tape recording: analog recording and PCM recording. PC
In the case of M recording, unless the peak value of the reproduced sound is known in advance, it is not possible to accurately determine the dynamic range and S/N before recording. Due to the nature of 20M recording, sudden odd-order distortion occurs when overload recording is performed for a short period of time. In analog recording, on the other hand, distortion occurs less often due to the saturation characteristics of tape.

In order to easily determine the recording level when the analog audio signal reproduced from the PCM audio reproduction device is recorded on the PCM recording device again, a reference tone signal indicating the level of the reproduced sound is sent from the PCM audio reproduction device. It would be extremely convenient if the By the way, PCM
Since an audio reproduction device includes audio signals with different signal levels for each section, for example when recording several pieces of music, a reference tone signal must also be generated for each section. However, conventionally, there has been no PCM audio reproduction device that sends out such a wide variety of reference tone signals.

[Problem that the invention seeks to solve]

In view of the above circumstances, an object of the present invention is to record each meaningful recording section of a recording medium (for example, in the case of music, a famous song).
It is an object of the present invention to provide a PCM audio reproducing device capable of generating a sine wave having an isometric amplitude at the maximum value of an audio signal in that section and transmitting it as a reference tone signal.

The sine wave generator is capable of outputting an audio signal in a switched manner, and is provided with means for storing information for controlling the sine wave generator in advance, and externally sets the recording section arbitrarily. It is assumed that a sine wave generator controlled by said means sends out a reference tone signal corresponding to the recording interval.

[Failure to solve the problem]

To solve the problem, there are two types of inventions depending on whether a digital method or an analog method is used to generate a reference tone signal.

First, a digital method will be explained.

The device of the first invention includes a level detection section that detects the section maximum level for each recording section with respect to the digital audio output from the digital signal section of the PCM audio reproduction device;
It is provided with a tone level recording section for recording the section maximum level, and a sine wave generating section, which will be described later. Here, the digital signal section is a temporary designation of a section that outputs left and right time-divided data before DA conversion of the playback device. Therefore, when listening to audio, the output of the digital signal section is input to the DA converter and output as left and right channel audio.

The sine wave generator has means for creating a digital sine waveform corresponding to the maximum audio output of the PCM audio reproduction device, and for multiplying the digital sine waveform by a coefficient determined by the section maximum level. After sequentially recording the section maximum level for each recording section in the tone level recording section, data of an arbitrary section is sent from the tone level recording section to the sine wave generating section by an external key control switch. At the same time, the output of the sine wave generator is
The signal is switched and input to the analog converter of the PCM audio reproduction device, and output as a reference tone signal for the section.

Next, the analog method of the second invention will be explained. The level detection section and tone level recording section are exactly the same as those in the above invention, but the sine wave generation section includes a reference sine wave oscillator corresponding to the maximum audio output of the PCM audio reproduction device,
and a programmable attenuator that gives the output of the oscillator an amount of attenuation determined by the section maximum level of each recording section.

After recording the section maximum level of each recording section in the tone level recording section, an external key control switch sends the data of an arbitrary section from the tone level recording section to the sine wave generation section and generates the sine wave. The output of the generator is switched with the output of the PCM audio reproduction device and output as a reference tone signal for the section.

[Effect]

Both the first invention and the second invention have a sine wave generating means with an amplitude corresponding to the maximum level (FS) of the PCM audio reproduction device. Then, the maximum level for each recording section is detected and recorded in advance.

In the first invention, the sine wave signal is output as a digital signal, and in the second invention, the sine wave signal is output as an analog signal.
Both have means for changing the amplitude according to the maximum level of each recording section.

When an arbitrary recording section is selected using an external key-controlled switch, the recorded maximum level signal changes the amplitude of the sine wave signal to the maximum level of that recording section. By switching this sine wave signal to the analog converter in the first invention and directly to the audio output terminal of the PCM audio reproduction device in the second invention, a reference tone signal is sent to the outside.

〔Example〕

The first invention will be explained with reference to the embodiment shown in FIG. 1A. The circuit shown in FIG. 1A includes a digital signal section t,
Level detection section 2. ) - level recording section 3. It is roughly divided into a sine wave generator 4A and an analog converter 5. The tone level recording section 3 stores, as information for controlling the sine wave generating section 4A,
Information regarding the maximum audio level of each recording section is recorded, and an external key-controlled switch 6 is used to output data for an arbitrary section, and the information is sent to the sine wave generator 4.

First, the procedure for storing maximum level information in the tone level recording section 3 will be explained. The level detection section 2 includes an absolute value detection circuit 21. Register ρ, comparison circuit Z3. When a digital signal from the digital signal section 1 enters an absolute value detection circuit 21, it detects whether it is positive or negative, and if it is a negative number, it is corrected to a positive number and output. When the illustrated signal A is larger than the signal B, the register n and the comparison circuit 23
Between the D circuits, the signal A is latched into the register n by the clock (1). Therefore, the output of the register 22 is always the maximum value of the signal being sent. The clock (1) is a clock signal for each word of the signal, and the reset signal is input for each section in which the maximum value is detected.

The maximum value is stored in the memo IJ 31 of the tone level recording section 3 at an address corresponding to the section number, for example, under the control of the memory control section 32. For address information,
In the case of music, the address corresponding to the song number or song name is determined as appropriate. The sine wave generator 4A generates a sine wave with a peak value corresponding to the maximum value of the audio signal in each section, as a digital value over time. Output as a relation (digital sine waveform). In other words, the clock (
2) is counted by the counter 41, and the addresses in the ROM (1142) are sequentially scanned. Here, the clock (2) is 2 fs, which is twice the frequency fs at which the left and right two channels are sampled.

The ROMfl) 42 is a read-only memory that stores the amplitude value at each time of a sine wave whose peak value is the maximum audio level of the PCM playback device, and this waveform is outputted to the outside by the sequential scanning.

This sinusoidal digital signal is multiplied by a constant multiplication coefficient in a multiplication circuit. This multiplication coefficient is stored in the read-only memory ROM (2143) and is selected and output when the section maximum level information is input from the memory 31 of the tone level recording section 3. Therefore, the switch control signal is output from the memory control section 32. When the signal is sent out, the switch S1 is connected to the (pl side) and the ROM (214
3, the multiplication coefficient is sent to the multiplication circuit 44, and the predetermined multiplication coefficient is multiplied by the maximum level of the PCM audio reproduction device, so that a digital sine waveform corresponding to the maximum level for each section is input to the analog converter 5. do. The multiplication coefficient is 1 when the maximum level value of the recording section is equal to the maximum level of the PCM audio reproduction device, and the multiplication coefficient corresponding to the maximum level value of each section is read from the ROM+2143.

The analog converter 5 converts the signal into an analog signal using a DA converter 51, and divides the signal into left and right channels using a multiplexer 52.
Filter 53(1): Outputs the reference-1 signal to the outside as an analog audio via 53(21).P
A CM recording device can easily determine its recording input level using either the left or right channel. The operations of the above-mentioned parts are performed by control signals on the control path of the digital signal section 1, but after the section maximum level is recorded in the memory 31, the operation is performed by the external key control switch 6.
Data in an arbitrary section is sent to the sine wave generator 4, and a reference tone signal for that section is output.

Next, the second invention will be explained with reference to the embodiment shown in FIG. 1B. In the circuit of FIG. 1B, the digital signal portion i,
Level detection section 2. ) - level recording section 3. is exactly the same as the first invention.

However, the sine wave generating section 4B does not include an (analog) sine wave oscillator 7 and a programmable attenuator 8. This is to determine the following. The section maximum level selected by the external key control switch 6 is transmitted to the programmable attenuator 8, and the switches Ss and Ss are switched from the audio output side (ql to the reference tone signal side (p). Then, a reference tone signal corresponding to the maximum level of each recording section is outputted to the outside.

In the first invention, in FIG. 1A of the embodiment, a ROM (2143) for generating a multiplier coefficient is provided in the sine wave generating section 4A, but it may be provided in the tone level recording section 3.

〔Effect of the invention〕

As described in detail above, 1. The PCM audio playback device of the present invention can immediately output a reference tone signal corresponding to the signal level of each meaningful recording section (for example, each individual in a song) as a reference tone signal. , P
This makes it extremely easy to set the recording input level on the recorder side when recording a PCM audio signal reproduced by a CM audio reproducing device. Furthermore, the present invention is applicable to all PCM recording systems such as compact disc players and audio tape recorders.

[Brief explanation of drawings]

The drawing shows an embodiment of the present invention, in which the sine wave generator is the first
FIG. 1B is a circuit block diagram that generates a digital wave in FIG. A and an analog wave in FIG. 1B. l...Digital signal section, 2...Level detection section, 3
...Tone level recording section, 4A, 4B... Sine wave generation section, 5... Analog conversion section, 6... Key control switch, 7... (Analog) sine wave oscillator, 8... Programmable attenuator, 21... Absolute value detection port-path, n
...Register, n...Comparison circuit, Sae...AND circuit, 31...Memory, 32...Memory control unit, 41
...Counter, 42...ROM (11,43...
・ROM+2), 44...multiplying circuit.

Claims (2)

[Claims] (1) Regarding the digital audio output from the digital signal section of the PCM audio playback device, a level detection unit that detects the section maximum level for each recording section, and a tone level recording section that records information regarding the section maximum level. and,
a sine wave generator having means for creating a digital sine waveform corresponding to the maximum audio output of the PCM audio reproduction device and multiplying the digital sine waveform by a multiplication coefficient determined by the section maximum level; After recording the section maximum level of each recording section in the level recording section, by using an external key control switch, data of an arbitrary section is sent from the tone level recording section to the sine wave generating section, and the sine wave A PCM audio reproducing device characterized in that the output of the generating section is switched and inputted to an analog conversion section of the PCM audio reproducing device, and outputted as a reference tone signal of the section. (2) a level detection section that detects the section maximum level for each recording section with respect to digital audio output from the digital signal section of the PCM audio playback device; and a tone level recording section that records the section maximum level; a sine wave generating section having a reference sine wave oscillator corresponding to the maximum audio output of the PCM audio reproduction device and a programmable attenuator that provides an attenuation amount determined by the section maximum level to the output of the oscillator; After recording in the level recording section, an external key control switch is used to send the data of an arbitrary section from the tone level recording section to the sine wave generation section, and to send the output of the sine wave generation section to the PCM audio playback device. A PCM audio reproducing device characterized in that it outputs a reference tone signal of the section by switching to an output.