1. Field of the Invention
The present invention relates to an active delay method which is capable of synchronizing a binaural hearing device stably by reducing a time difference which may be produced due to wireless connection of two hearing devices, and a wireless binaural hearing device using the same method.
2. Description of the Related Art
In recent years, approaches have been frequently researched which uses a binaural hearing device to strengthen user's hearing. A binaural hearing device is a device which processes signals acquired through two or more hearing devices or microphones attached to ears or a neck and transfers the processed signals to user's ears. Use of the binaural hearing device can improve user's hearing and allows the user to detect a position of a sound source reliably.
However, existing hearing devices have to be equipped with several microphones connected to each other by wires, which detracts from the beauty.
To avoid such a demerit, many attempts to transmit signals of a binaural hearing device by wireless have been made. Such attempts have focused on a wireless transmission system which can transmit signals acquired by one hearing device to another hearing device.
However, such a wireless transmission system cannot avoid producing a signal delay for signal modulation-demodulation and verification, as compared to a wired transmission system. General wireless systems may be used with no problem since they recognize a sound source to be just a little apart from them even if a time delay of 10 to 50 ms is produced. However, for a binaural algorithm, a delay measured in microphones is a very important factor as shown in
However, such wireless binaural hearing devices require wireless transmission time of about 10 to 50 ms, which may result in low sound recognition.
To overcome the above problems, it is an object of the invention to provide a wireless binaural hearing device which is capable of eliminating the detraction from the beauty due to wired connection of microphones, preventing incorrect detection of a position of a sound source or paralalia due to a time delay which is produced in a wireless binaural hearing device and reducing noises due to a time difference between both hearing devices, thereby providing a binaural hearing device with high quality.
To achieve the above object, according to the first aspect of the invention, there is provided a binaural hearing device with improved performance through an active delay, including: a first hearing device including a first microphone, an amplifier and a wireless transmitter; and a second hearing device including a second microphone, an amplifier, a wireless transmitter, a wireless receiver which receives a signal from the wireless transmitter, an active delay circuit which synchronizes the received signal with a signal acquired by the second microphone, a neural network which synchronizes the delayed signal, and a speaker which converts the synchronized signal into a voice signal.
Preferably, the active delay circuit includes: a RSSI measuring unit which acquires strength of the received signal; and an adaptive delay element which acquires a time delay per wireless data packet of the received signal.
Preferably, the adaptive delay element includes a local oscillator and a PLL circuit.
According to the second aspect of the invention, there is provided an active delay method in a binaural hearing device, comprising the steps of: (a) acquiring sound signals through microphones of a first hearing device and a second hearing device and converting the acquired sound signals into digital signals; (b) transmitting the signal acquired in the first hearing device to the second hearing device by means of a RF transmitter of the first hearing device; (c) receiving the signal by means of a RF receiver of the second hearing device; and (d) actively delaying the wirelessly received signal to synchronize the signal of the second hearing device with the signal of the first hearing device.
Preferably, the step (a) includes the steps of: acquiring the sound signals through microphones; amplifying the acquired sound signals and filtering the amplified signals in a predetermined frequency band; and converting the filtered signals into digital signals.
Preferably, the step (d) includes the steps of: acquiring a RSSI and a time delay; and synchronizing the signals of the first and the second hearing devices by adaptively delaying the signals using the acquired RSSI and time delay.
Preferably, the time delay is a time delay per wireless data packet.
Preferably, the data packet contains time data.
Preferably, the synchronizing step includes the step of acquiring the time delay per wireless data packet and then determining a total time delay using a neural network.
Preferably, the synchronizing step includes the steps of: comparing the signal received in a RF receiver of the second hearing device with a signal of a local oscillator; and synchronizing phases of the signals of the first and the second hearing devices using a PLL circuit.
According to the present invention, it is possible to prevent incorrect detection of the position of the sound source or paralalia due to a time delay which is produced in the wireless binaural hearing device and reduce noises due to a time difference between both hearing devices, thereby providing a binaural hearing device with high quality.
In addition, this invention provides a hearing device which predicts a possible time delay by detecting conditions of wireless channel, stores signals in a temporary repository, and outputs the signals in synchronization with a synchronized system. In addition, this invention provides an improved binaural hearing device and an active delay method which are capable of inserting time data in a form of data in preparation for improper data transmission to facilitate signal data synchronization even in case of failure of data transmission.
The above and other objects, advantages, features and methods will be better understood when reading the following detailed description and the accompanying drawings. However, it should be understood that the present invention is not limited to the disclosed embodiments but may be embodied in other various forms. The disclosed embodiments are provided to describe the present invention in detail so that those skilled in the art can practice the technical ideas of the present invention.
In the drawings, elements of the embodiments are not shown in a limited sense but may be exaggerated for clarity. Throughout the drawings, same reference numerals denote same or similar elements.
In the specification, as used herein, the term “and/or” is meant to include at least one of elements arranged before and after. In addition, a singular form “a” or “an” is meant to include a plural form unless stated specifically otherwise. In addition, as used herein, the term “comprise(s)” or “comprising” is meant to include or add one or more of elements, steps, operations, devices and apparatuses other than those mentioned in the specification.
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
Here, the first hearing device and the second hearing device mean a left hearing device and a right hearing device, respectively, but it is not necessarily meant to specify one of them. For example, this invention proposes to receive a signal entering the microphone of the second hearing device by a wire at the first hearing device by wireless and synchronize the wirelessly received signal with a signal entering the microphone of the first hearing device through an active delay.
With this configuration, it is possible to prevent incorrect detection of the position of the sound source or paralalia due to a time delay which is produced in the wireless binaural hearing device and reduce noises due to a time difference between both hearing devices, thereby providing a binaural hearing device with high quality.
Referring to
In this manner, in this invention, it is possible to search interference of a wireless network signal and RSSI and actively delay the signal using the searched RSSI. The delayed signal is transferred to a binaural hearing device algorithm and is transmitted to the speaker. As shown in
In this embodiment, the right hearing device is designated as the first hearing device and the left hearing device is designated as the second hearing device. The first hearing device or the right hearing device includes a microphone, an amplifier, a band pass filter, an analog to digital converter (ADC) and a RF transmitter.
As shown in
The second hearing device receives the digital signal in a RF receiver, acquires signal strength and a time delay per and packet of signal data, determines a total time delay, synchronizes its signal and the signal of the first hearing device using a neural network (or binaural algorithm), and output the synchronized signals to the speaker.
As shown in
In this case, synchronization of both hearing devices may be varied over a long period of time due to an inaccurate crystal oscillation frequency of each system. If the hearing device is used for more than a day, synchronization of time data in a packet may be incorrect. Thus, this invention proposes a synchronization method using a PLL circuit in order to overcome this problem.
The PLL circuit used herein is a circuit which detects a phase difference between an input signal and an output signal, controls a phase of an output signal generator with a voltage proportional to this phase difference, and makes the phase of the input signal equal to the phase of the output signal, such as an automatic phase control loop including a phase comparator, a low pass filter, an error amplifier and a voltage controlled oscillator. The PLL circuit is frequently used as a frequency oscillation source of a frequency synthesizer or a radio transceiver.
In this manner, in this invention, it is possible to acquire a high quality hearing device output signal by synchronizing phases of signals using the PLL circuit to compensate for low accuracy due to a prolonged use of crystal oscillation frequency of each system.
In more detail, external sound signals are acquired in microphones of both hearing devices (S100), and the sound signals are converted into digital signals through an amplifier, a band pass filter and an ADC of each hearing device (S110). The converted signals are transmitted to the second hearing device via the RF transmitter of the first hearing device (S200), the signals are received in the RF receiver of the second hearing device (S300), and a total time delay is determined after an RSSI and a time delay per wireless data packet (S400).
Once the total time delay is determined, the received signal is delayed by the time delay and is synchronized with the signal of the second hearing device. In this embodiment, in order to overcome difficulty in data synchronization due to a prolonged use of the binaural hearing device, the received signal is compared with a signal of a local oscillator (S410), and the signals of the first and the second hearing devices are delayed by the time delay using the PLL circuit to synchronize phases of both signals (S420).
As described above, this invention provides a method of synchronizing a plurality of wireless hearing devices and a system using the same. In particular, this invention provides a hearing device system which predicts a possible time delay by detecting conditions of wireless channel, stores signals in a temporary repository, and outputs the signals in synchronization with a synchronized system. In addition, this invention provides an improved binaural hearing device and an active delay method which are capable of inserting time data in a form of data in preparation for improper data transmission to facilitate signal data synchronization even in case of failure of data transmission.
Although a few exemplary embodiments have been shown and described, it will be appreciated by those skilled in the art that adaptations and changes may be made in these exemplary embodiments without departing from the spirit and scope of the invention, the scope of which is defined in the appended claims and their equivalents.
Number | Date | Country | Kind |
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10-2011-0062399 | Jun 2011 | KR | national |