JPS5975412A - Device for reproducing digital record - Google Patents

Abstract

PURPOSE:To set the power supply to a digital reproducing system to the turned off condition simultaneously with the monitoring of analog signals and to realize sound recording of a long time, by supplying an ADC output to a DAC input under the sound recording condition of a digital record reproducing device using a portable power source. CONSTITUTION:The output signal of an ADC circuit 20 is supplied to a DAC circuit 26 via a switch 41 and the supply of the output voltage of a DC-DC converter 37 to a reproducing system 27 is interrupted. Therefore, the output signal of the ADC circuit 20 is respectively supplied to OUTL and OUTR and monitor terminals ML and MR after it is DA-converted at the DAC circuit 26. As a result, monitoring of sound recording signals can be performed under a condition which is nearly same as the case where monitoring is performed under the EE condition of a VTR and excellent reproduction of digital records can be performed by extending the continuous sound recording time by a portable power source of a battery, etc.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] Jin's invention achieves the following by reducing power consumption as much as possible.
The present invention relates to a PCM recording/playback device suitable for performing PCM recording and playback outdoors, for example.

[Technical background of the invention]

2. Description of the Related Art Recently, in the field of audio equipment, a PCM recording/playback device (that is, a digital recording/playback device) using PCM technology has been developed.

This advanced PCM recording/playback device operates on the principle that during recording, the audio analog signal is once converted into a digital signal and recorded on a magnetic tape, and during playback, the digital signal reproduced from the magnetic tape is converted into an audio analog signal. This will be realized in the future.

Specifically, an audio analog signal is sampled at a predetermined period, and the sampled audio analog signal is converted from Cyan to digital by, for example, a well-known successive approximation type analog-to-digital converter. bm childization and encoding. During recording, this denotal signal is subjected to addition of an error correction code, addition of an error detection code, and well-known interleaving processing, and is then processed by a video recorder (hereinafter referred to as VTR) superimposed on, for example, an NTSG standard television signal. (named). On the other hand, the NTSC standard television reproduced from this video chip recorder), the digital data (such as sampled words, error correction codes, error detection codes, etc.) demodulated and extracted from the JIN signal are as follows:
After being subjected to dinterleaving processing, the interleaved sampled word is subjected to error detection and error correction using the error detection code and error correction code, and the original analog signal is converted into a quadruple signal. The signal is then converted into a signal (sampled word) equivalent to the encoded digital signal. This sampled word is adapted to be restored to the original audio analog signal by a digital-to-analog converter.

In other words, by converting audio analog signals into all-digital signals, it is possible to overcome the technical limitations associated with conventional analog tape recorders such as cassette tape recorders, such as the physical characteristics of the maximum magnetization level of the magnetic tape used as the recording medium. High-quality recording and playback can be achieved by completely eliminating any negative effects on acoustic characteristics caused by mechanical precision or the like.

In order to be able to perform high-quality recording and playback of live performances performed outdoors, for example, a PCM recording and playback device that can operate even in places where an AC 1j+ source cannot be used, as shown in Figure 1, has been developed. is being developed.

That is, for example, the two left and right audio analog signals, which are the recorded signals supplied from a microphone or the like, are connected to the terminals INL t INB and the amplifiers 11 and 12, respectively.
The well-known re-emphasis is carried out via the re-emphasis circuit 13,14. Each output signal of these Norien 7 assist circuits 13+14 is passed through a low-pass filter (hereinafter referred to as LPF) 15°16 whose cutoff frequency is set at 20 kHz, for example.
respectively through the sample and hold circuits 17
．． It is supplied to each of the 18 input terminals, sampled and held every 22.6 μs, and then output to the mixing circuit No. 9.
is supplied to a pair of input terminals of.

The respective output signals of these sample and hold circuits 17 and 18 are multiplexed by the mixing circuit 9 so that the left and right channels are alternately switched every 11.3 μs, and then sent to an analog-to-digital conversion circuit (hereinafter referred to as ADC circuit) 20. It is designed to be supplied to the input terminal of The output signal of the mixing circuit J9 is as follows.

The ADC circuit 20 synchronizes the left and right channels with switching (
For example, it is converted into a 14-bit serial digital signal (generally called a sampling word) every 11.3 μs.

The sampled words that are continuously output from the output terminal of the ADC circuit 20 are subjected to processing such as well-known interleaving processing, addition of error correction codes and error detection codes, etc. For example, it is superimposed on the NTSC standard television signal by the amplifier 22 and sent to the output terminal 0.
Video cheap recorder (hereinafter referred to as VTR) via UTv
23 video input terminals (referred to as ), and is supplied to the TVR
It can be recorded on No. 23 magnetic tape.

Further, the NTSC standard television signal reproduced from the magnetic tape is supplied to the synchronization signal separation circuit 24 via the input terminal INv'i and demodulated, so that the sample signal is interleaved by the recording processing circuit 21. The signals are converted into signals equivalent to the code word, error correction code, and error detection code and supplied to the input terminal of the reproduction processing circuit 25, and only a synchronization signal (not shown) is separated and supplied to, for example, a clock signal generation circuit (not shown). A clock signal synchronized with the synchronization signal is supplied to the reproduction processing circuit 25.

The sampling word, the error correction code, and the error detection code output from the synchronization signal separation circuit 24 are subjected to a dinterleave process, which is opposite to the interleave process, and an error detection code and an error correction code, by the reproduction processing circuit 25. Based on this, erroneous words are detected and corrected in the sampled word. This error-corrected sampling word is converted into a digital-to-analog converter (hereinafter referred to as a DAC circuit) in synchronization with the clock signal.
260 input terminal. At the same time, the reproduction processing circuit 25 supplies the clock signal and various control signal generation signals to a predetermined portion (not shown). The synchronizing signal separation circuit 24 and the reproduction processing circuit 25 are combined to form a digital reproduction yarn 27.

The sampling word supplied from the reproduction processing circuit 25 is
The DAC circuit 26 converts the signal into a signal equivalent to the multiplexed analog signal derived from the mixing circuit 19 in synchronization with a predetermined control lI signal, and supplies the signal to the input terminal of the separation circuit 28. It has become so. The multiplexed analog signal output from the DAC circuit 26 is separated into two systems of analog signals corresponding to the analog signals of both the left and right channels by a separation circuit 28 that operates according to a predetermined control signal. There is.

The analog signals separated into the two systems are correspondingly outputted from a pair of output terminals of the separation circuit 28, and a pair of low/mother filters (LPF) 29. each having a cutoff frequency set to 20 kHz. 30 and a pair of playback output terminals 0UTL, 0UTR and a monitor terminal ML? As a result, the sampled words recorded on the magnetic chip of the VTR 23 are supplied to the battery 33 or AC so as to be restored to the audio analog signals of both the left and right channels. An AC/DC adapter 34 that can obtain a predetermined DC power from a power source can be selectively used. That is, the DC voltage of the battery 33 is directly applied to one input terminal of the power supply switching circuit 35, and the DC voltage output from the AC/DC adapter 34 is applied to the other input terminal of the power supply switching circuit 35. The terminal is connected to the other input terminal of the power supply switching circuit 35 via a connector 36.

Further, the AC/DC adapter 34 is connected to the connector 3.
A predetermined DC voltage (hereinafter referred to as "connector w", "detection voltage") is applied to the above-mentioned DC voltage separately from the DC voltage supplied to the other input terminal of the power supply switching circuit 35 so that the connection status kIel of the above-mentioned power supply switching circuit 35 can be output. It is designed to be supplied to the control input terminal of the power supply switching circuit 35 ◇With this! ], the DC voltage output from the battery 33 and the AC/DC adapter 34 is AC when the connector 36 is connected.
The DC voltage output from the /DC adapter 34 is supplied to each input terminal of the DC/DC converter 37 via the power supply switching circuit 35, and conversely, when the connector 36 is disconnected, the output of the battery 33 is DC voltage is DC/
The DC/DC converter 37, which is supplied to the input terminal of the DC converter 36, derives all DC voltages with different voltage values and polarities from the DC voltage supplied via the power supply switching circuit 35, for example. At the same time, the power is supplied to predetermined power terminals of various parts (not shown).

The device shown in FIG. 1 except for the VTR 23 is called a PCM grosser.

[The pinnacle of background technology]

However, the portable PCM recording and playback device mentioned above,
It is complex and has a reproduction system and a recording system that are each substantially completely independent, and its power consumption is extremely large compared to an analog tape recorder. Also,
This PCM recording/playback device uses the signal supplied to the input terminal of the VTR 23 as one of the! EE (E) output to the output terminal
For example, if the recording processing circuit 2 and the video amplifier 2
In order to make it possible to monitor the digital recording system, the reproduction system is always turned on even in the recording state, which further increases the total power consumption. For this reason, when using the battery 41, sufficient time P
The commercial recording and playback device could not be operated.

On the other hand, in the apparatus shown in FIG. 1, most of the reproduction system is completely turned off, and each signal supplied to the input terminals NL and NR, for example, is turned off. 1. If you monitor directly, it will consume less power and can be used for a long time using a battery, but it will not be possible to monitor including the digital recording system.

[Summary of the invention]

The present invention is equipped with a portable power source, records digital data obtained by converting analog signals from all analog to digital in a recording state into a digital recording system (Cf-precoder), and records the playback signal of the tape recorder in a playback state. In a digital recording and reproducing device that converts all digital data obtained by using a digital reproduction system and outputs it, the analog-to-digital converter outputs a digital-to-analog sound using the above-mentioned portable source. It is characterized by comprising a first means for supplying the analog signal to an input section of a converting section and making it possible to monitor the analog signal, and a second means for turning off all power to the digital reproduction system. It is something to do.

[Purpose of the invention]

This invention was made in view of the above points, and for example, V
To provide a complete digital recording and reproducing device capable of monitoring a recording signal in a state substantially the same as when all monitoring is performed in the Eg state of a TR, and extending the continuous recording time using a portable power source such as a battery. The purpose is to

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to all the drawings.

FIG. 2 shows a main part of an embodiment of a digital recording/reproducing apparatus according to the present invention. However, in FIG. 2, the same parts as in FIG. 1 are given the same reference numerals and their explanations will be omitted.

That is, the output terminal of the regeneration processing circuit 25 is connected to one input terminal 1. of the switching circuit 4. It is connected to the.

The output terminal of the ADC circuit 20 is connected to the other input terminal (2) b of the first switching circuit 4.

The first switching circuit 4 is constructed of, for example, a data multiplexer, and has an output terminal connected to the input terminal of the DAC circuit 26, and a control input terminal that connects the switch S. is grounded through. As a result, the first switching circuit 4 outputs all the signals from the input terminal 8 when the switch S is off, and outputs the signal from the input terminal I when the switch S is off. be.

Further, the power input terminal of the digital reproduction system 27 is connected to the DC/DC converter 37 via the second switching circuit 42.
is connected to an output terminal that provides a predetermined voltage. 2nd above
The switching circuit 42 is constituted by a switching element such as a relay or a transistor, and its control input terminal is connected to the connection midpoint between the control input terminal of the first switching circuit 4 and one end of the switch S, and the switch The OFF state and the ON state correspond to the ON and OFF states of S.

That is, in the apparatus configured as described above, when the switch S is off, the output signal of the digital reproduction system 27 is supplied to the DAC circuit 26, and the reproduction signal of the VTR 23 is supplied via the digital reproduction system 27. The digital signal obtained by this is connected to the multi-output terminal 0UTL as described above.
*0UTR is converted into a 2-channel analog signal and output.

On the other hand, when the switch Sk is turned on in the recording state, the first switching circuit 41 also supplies the output signal i of the ADC circuit 20 to the DAC circuit 26;
The switching circuit 42 cuts off the output voltage of the DC/DC converter 37 that is being supplied to the digital reproduction system 27.

As a result, the output signal of the ADC circuit 2θ is converted into a 7" analog signal by the DAC circuit 26, and then output as a separated 2-channel analog signal to the output terminals OU'TL yOUTR and the monitor. It can be obtained from terminals ML and MR and can be monitored.

In this case, monitoring is performed, for example, by driving headphones through an intensifier for each output signal of each monitor terminal MLIMR, and for each input terminal NLfIN.
When the amplitude of the signal supplied to the RK exceeds the maximum input level of the ADC circuit 20, distortion occurs in the sound reproduced by the headphones, and it is easy to see that the recording level A is inappropriate. .

Also, in this state, the digital playback system 27 is powered off, so the power consumption is reduced accordingly, making it possible to record for a long time, which is extremely advantageous.

Apart from this, the main parts of the digital recording/reproducing apparatus according to the present invention can be configured as shown in FIG. 3, for example. However, in FIG. 3, the same parts as in FIG. 2 are designated by the same reference numerals, and the explanation thereof will be omitted.

That is, the output signal of the ADC circuit 9 and the output signal of the digital reproduction system 27 are selectively applied to the input terminal of the DAC circuit 26 by a switching circuit 53 composed of an AND-OR select circuit 5 and an inverter 62. It is said that it can be supplied to many countries. Further, the DC/DC converter 3 provided to the digital reproduction system 27
The output voltage of 7 can be turned on and off by a switching circuit including a resistor R1, a transistor Q relay, and a diode D.

Each of the above switching circuits L'' and 54 are OR circuits 55
The gJ exchange is controlled in each case.

This OR circuit 65 has a resistor R21J with fi 'I'
Connector connection production voltage that is level-converted to TL level is supplied, and the recording switch leaks and the playback switch SP
1 resistor R4+R11t NAND circuit 56.57 A flip 70f is provided to supply the output signal of the switching i'u II control circuit. In the digital recording and reproducing device equipped with the connector 36, the AC/DC adapter 34 is connected.
When the connector continuity detection voltage is obtained, the switching circuit or switching circuit 54 supplies the output voltage of the DC/DC converter 37 to the digital reproduction system 27, regardless of the output of the switching control circuit. The switching circuit supplies an output signal to the DAC circuit 26 of the digital reproduction system 27. When the VTR 22 is set to the FJF state, the digital self-reproducing device becomes able to monitor the analog signals provided to each input terminal INL t INn.

On the other hand, when the connector connection effect voltage cannot be obtained in a state where the battery 33 is driven by the output voltage of the battery 33, the switching circuits "L" and "D" each output the output signal of the "switching control circuit" (of the NAND circuit 56). switching is controlled by the output signal). In other words, when the recording switch is operated and the output terminal level of the AND circuit 56 becomes low level,
The OR circuit 55 completely prohibits the switching circuit from supplying the output voltage of the DC/DC converter 37 to the digital reproduction system 27. Along with this, the switching circuit also outputs the output signal '!' of the ADC circuit J9. r It is supplied to the input terminal of the DAC circuit 26. As a result, the digital recording and reproducing apparatus having the configuration shown in FIG.
The power consumption is reduced by the amount that the alarm is turned off, and long-time recording operation using the battery 33 is possible, which is good.

When the output terminal level of the NAND circuit 56 with the playback switch SP operated reaches a high level, the switching circuit turns on the power to the digital playback system 27, and the switching circuit outputs the output signal iDA of the digital playback system 27.
It is supplied to the C circuit 26. Accordingly, the digital recording/reproducing apparatus having the configuration shown in FIG.
playback operation is possible.

That is, by having the configuration shown in FIG. 4, the digital recording and reproducing apparatus can monitor the VTR 23 in the EE state in the recording operation state using alternating current using the AC/DC adapter 34. The recording operation condition is extremely good, with low power consumption and long continuous recording operation possible.

It goes without saying that other individual modifications and applications are possible without departing from the spirit of the invention.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to monitor recording signals in substantially the same state as when monitoring is performed in the EE state of a VTR, and the continuous recording time using a portable power source such as a battery can be extended. It is possible to provide an excellent digital recording and reproducing device that achieves the above-mentioned characteristics.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a conventional digital recording and reproducing device, FIG. 2 is a block diagram showing a digital recording and reproducing device according to the present invention, and FIG. 3 is a block diagram showing the machine part of another embodiment. be. 11.12...Amplifier, 13.14...Pre-emphasis circuit, 15T16...LPF% 17.18.
... S/H circuit, 19... Mixed circuit, 20... AD
C circuit, 21... Recording processing circuit, 22... Video amplifier, 23... VTR, 24... Synchronizing signal separation circuit, 26... Playback processing circuit, 26... DAC circuit, 2
7... Digital reproduction system, 28... Separation circuit, 29.
30...LPF, 31.32...De-emphasis [
Lsa...Battery, 34...AC/DC adapter, 35...' power supply switching circuit, 36...Connector,
37... DC/DC converter, 41... First switching circuit, 42... Second switching circuit, S... Switch.

Claims (1)

[Claims] Fully equipped with a portable power source, in the recording state, the analog signal is converted into analog-to-digital and digital data is recorded on the tape recorder via the digital recording system, and in the playback state, the playback signal of the tape recorder is transferred to the digital playback system. In a digital recording and reproducing device that converts digital data obtained from digital to analog and outputs it,
a first means for supplying the output of the analog-to-digital converter to the input section of the digital-to-analog converter to monitor the analog signal in a recording state using the portable power source; and the digital playback system. A digital recording and reproducing device M is characterized in that it is equipped with a second means for bringing the fr' into the original state.