As a continuation of our “How Does This Work” series it’s time to tackle digital hearing aids. While analog hearing aids still exist they are quickly being left behind by the overwhelming amount of new digital hearing aids. Frequently though there are questions as to why is digital is better and how does it work. Below we’ll try to cover some of the broad topics to clear some things up.
To begin it might be important to understand how a signal is processed digitally.
First an acoustic signal is converted to an electrical analog signal from the microphone stage of the hearing aid. After this conversion, a frequency filter then reduces the possible distortion of the input signal. The signal is then “sampled” a number of times per second. Usually, the sampling rate is 10,000 times per second, sometimes more.
From that point the analog signal is then converted to its digital equivalent by an analog to digital (A/D) converter. Every sample then receives its own digital code and binary numbers (O and 1) are used to represent the digital value of each sample. After the digitization of the signal, the digital values are processed by a central processing unit (CPU) or a microprocessor. The digital values can be manipulated and grouped in specific ways. The microprocessor contains a myriad of algorithms. An algorithm is a system of instructions that operates in a manner determined by a set of mathematical rules and equations. If the algorithm is a dedicated one, it performs a specific task relative to the processing of the input signal. For instance, one algorithm may control the frequency response of the instrument, another may control loudness growth, a third may function to enhance the speech signal in a background of noise, etc. After the microprocessor has performed its tasks, the digitized signal must be converted back to its analog equivalent. This is accomplished at the digital to analog (D/A) conversion stage. When the digitized signal is converted back to its analog stage, it is filtered again, to prevent distortion. It is then amplified in the conventional manner and submitted to the receiver (speaker) of the hearing aid.
The advantages of this process is that all the signals coming in now can be modified in a number of ways. New parameters for different environments can be set making your hearing aid truly customized to your needs and giving you the clearest hearing in any situation.
Schmidt’s Optical and Hearing™ believes that staying current with the newest technology is important in providing you with the best hearing care possible. We carry a large variety of these digital hearing aids in stock so you can receive a custom fit and leave with your new hearing devices the same day. Our Board Certified Hearing Aid Specialist is here to help you with all your hearing, fitting, adjusting, and repair needs. Call today to schedule your FREE comprehensive hearing screening at 772-286-4327!
For additional information feel free to visit Audiologyonline.com.