JP2012042732A - Voice transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a voice transmission system suppressing the degradation of a signal even if passing through multistage speech processing devices.SOLUTION: (1) An AD converting device 2 which converts an input analog voice signal into a digital signal, (2) a plurality of speech processing devices 3 which performs various processing on a digital voice signal, and (3) DA converting device 4 which converts the processed digital signal into any analog voice signal to output are connected to a router 1. An external terminal connected to another speech processing system 10, and a console 11 which controls each apparatus constituting this system are connected to the router 1. A signal transferred between each device 2, 3 and 4 and the router is made to be a 32 Bit floating point format.

Description

  The present invention relates to an audio transmission system formed by connecting a plurality of audio processing devices.

  As formats for transmitting digitized audio signals, AES-3 (Audio Engineering Society), SPDIF (Sony Philips Digital Interface) and the like are known. A similar transmission method is also adopted in recent network audio. In these audio formats, audio data is transmitted after being converted to a fixed point system. Generally, it is transmitted at 16bit / 44.1kHz due to the limitation of the CD format, and at 24bit / 96kHz even in a device with higher sound quality. Note that 24-bit data has 256 times the resolution of 16-bit data.

  On the other hand, as an AD or DA converter for converting audio data, a device corresponding to 32 bits has been put into practical use, and the number of bits tends to increase in the future. However, since the maximum number of bits used in the audio system is 24 bits as described above, a 24-bit fixed point format is necessary for AD or DA conversion. Even if the AD or DA converter uses a high bit number such as 32 bits, the accuracy is limited by the number of bits in the transmission path (maximum 24 bits). The same thing occurs when audio signal processing such as equalizer is performed in the 32-bit floating point format on the audio adjustment console.

  Further, even when a plurality of audio signal processing apparatuses are connected as in Patent Document 1 and Patent Document 2, it is necessary to convert to a 24-bit fixed-point format each time a signal is input to or output from each apparatus. In that case, for example, when dealing with an audio signal that uses only a few lower bits, the number of effective bits of the signal is reduced when converted to fixed point, and the signal processing device in the next stage performs signal processing. Signal distortion increases and its quality decreases.

Japanese Patent Laid-Open No. 2002-169597 JP-T-2002-512747

  The present invention has been proposed in order to solve the problems of the prior art as described above, and its purpose is that when a plurality of audio processing devices are connected, there is little degradation in quality between the devices, An object of the present invention is to provide an audio transmission system that enables high-quality audio transmission.

  In order to achieve the above object, an audio transmission system of the present invention includes an AD conversion device that converts an input analog audio signal into a digital signal, a plurality of audio processing devices, and an arbitrary analog audio signal from the processed digital signal. The DA converter that converts the signal to output is connected via a router, and the signal that is exchanged between the AD converter, the plurality of sound processing devices, the DA converter and the router is in a 32-bit floating point format. Features.

Further, the present invention includes the following embodiments.
(1) At least one of the plurality of sound processing devices has a high accuracy of 32 bits or more as an internal calculation accuracy.
(2) The router has an external terminal connected to another audio processing system, and outputs a digital signal in 32-bit floating point format from this external terminal.
(3) A control console is connected to the router, a control signal is transmitted from the control console to each device connected to the router, and status data of each device is received by the console.

  In the audio transmission system of the present invention, the digital signal converted into the 32-bit floating point format by the AD converter is always exchanged in the same 32-bit floating point format between a plurality of audio processors via the router. The digital signal processed by the audio processing device is also sent to the output DA converter in the same 32-bit floating point format. As a result, even if it goes through many devices connected to the router, it is not converted to a low resolution format like the 24-bit fixed-point format between them, and a high-precision 32-bit floating-point format can be maintained. Signal quality is maintained.

1 is a block diagram showing the configuration of Embodiment 1 of the present invention. The block diagram which shows the flow of the signal processing in this invention.

  Hereinafter, the configuration of the first embodiment of the present invention will be specifically described with reference to FIG.

  In FIG. 1, reference numeral 1 is a router, 2 is an AD converter that converts an input analog audio signal into a digital signal, 3 is a plurality of audio processing devices, and 4 is a digital signal that has been processed and converted into an arbitrary analog audio signal The D / A converter that outputs the data. The AD conversion device 2, the plurality of sound processing devices 3, and the DA conversion device 4 are connected to the router 1, respectively. Further, the router 1 is connected to an external terminal connected to another voice processing system 10 and a console 11 for controlling each device constituting the system.

  The digital signal transmitted / received between the router 1 and each device is a 32-bit floating point format signal, and the digital signal output from the external terminal of the router 1 to another audio processing system 10 is also a 32-bit floating point format signal. is there. Therefore, the AD converter 2 that converts an analog audio signal into a digital signal has a function of generating a digital signal in a 32-bit floating-point format when the input analog audio signal is sampled and converted into a digital signal. Further, the DA converter 4 converts a 32-bit floating-point format digital signal distributed from the router into, for example, a 24-bit fixed-point format signal and outputs the signal to an existing audio system.

  Between the router 1 and the control console 11, a control signal transmitted from the control console 11 to each device 2, 3, 4 connected to the router 1 or a state of each device 2, 3, 4 is displayed. A control signal for confirmation on the console is transmitted and received. The control signal may be a signal having a format different from that of the digital audio signal distributed by the router 1.

  Each audio processing device 3 connected to the router 1 can use an equalizer, an effector, an amplifier or the like used in an audio adjustment console used in a broadcasting station or other audio equipment. In this case, each audio processing device 3 does not necessarily have to process a signal in the 32-bit floating point format. A higher precision signal may be processed, but in that case, it is necessary to provide a conversion device that converts a 32-bit floating point format signal and a higher precision signal at the input / output portion of each audio processing device 3. is there. In addition, as each audio processing device, a device that processes a signal of a 24-bit fixed-point format that has been widely used in the past is inappropriate because signal degradation occurs.

The operational effects of the first embodiment having the above-described configuration will be described with reference to FIGS.
FIG. 2A shows a conventional technique. Each of the AD conversion device 2 and the DA conversion device 4 which are input / output devices generates or outputs a signal of a 24-bit fixed-point format. Therefore, the transmission format between the input / output devices 2 and 3 and the router 1 is also a 24-bit fixed point. In this conventional technology, even though each signal processing device 3 can perform high-precision processing such as a 32-bit floating point format, the input / output unit of each signal processing device 3 has a higher accuracy than a signal in 24-bit fixed-point format. It is necessary to perform conversion processing with this signal. As a result, in the case of passing through the multistage signal processing device 3 as shown in FIG. 2A, deterioration of the digital signal to be processed is inevitable.

  On the other hand, in the system of this embodiment, each of the AD converter 2 and the DA converter 4 which are input / output devices generates or outputs a signal of a 32-bit floating point format, and signals between each device and the router in that format. Give and receive. As a result, even if the audio processing device 3 passes through a large number of stages as shown in FIG. 2B, the digital signal is not deteriorated, and the high quality of the output signal can be maintained even if various processes are applied.

DESCRIPTION OF SYMBOLS 1 ... Router 2 ... AD converter 3 ... Voice processor 4 ... DA converter 10 ... Other voice processing systems 11 ... Console

Claims (3)

An AD converter that converts an input analog audio signal into a digital signal, a plurality of audio processors, and a DA converter that converts the processed digital signal into an arbitrary analog audio signal and outputs it are connected via a router. And
A voice transmission system, wherein a signal exchanged between the AD converter, the plurality of voice processors, the DA converter and the router is in a 32-bit floating point format.   The audio transmission system according to claim 1, wherein the router includes an external terminal connected to another audio processing system, and outputs a digital signal in a 32-bit floating point format from the external terminal. The control console is connected to the router, a control signal is transmitted from the control console to each device connected to the router, and status data of each device is received by the console. The voice transmission system according to claim 2.

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