An introduction to electronics
An introduction to electronics

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

An introduction to electronics

4.3  Recording and analysing speech

Generally, sound waves are much more complicated than a wave made by humming a single note or the sound made by an electric toothbrush. For example, Figure 23 shows the waveforms generated by someone saying ‘yes’ followed by ‘no’. Let this be called Recording A.

Described image
Figure 23  Recording A: ‘yes’ followed by ‘no’


Each of the bursts of sound shown in Figure 24 is another recording of a person saying either ‘yes’ or ‘no’. Let this be called Recording B. Comparing Recording B with Recording A, which of the bursts of sound in Recording B is ‘yes’ and which is ‘no’?

Described image
Figure 24  Recording B


The left sound burst in Recording A has a long tail, presumably caused by the long ‘s’ sound at the end of ‘yes’. The right sound burst does not have this tail. In Recording B, the right sound burst has a tail but the left sound burst does not. From this, it can be guessed (correctly) that the left sound burst in Recording B is ‘no’ and the right sound burst is ‘yes’.

The fact that different words result in different wave patterns underlies the technology of speech recognition. This technology has evolved to a high performance level over the last half century, but it has overcome some formidable problems. For example, are one person’s speech patterns the same as another’s?

Return to Interactive 1 (which you should still have open in a separate tab) and spend five or ten minutes experimenting by making your own sounds. If you hum a low note, are you able to calculate its frequency? Can you distinguish the patterns when you say ‘yes’ and ‘no’? Are your ‘yes’ and ‘no’ wave patterns similar to those shown in Figure 23?

When you have finished, close the interactive.


Take your learning further371

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses372.

If you are new to university level study, we offer two introductory routes to our qualifications. Find out Where to take your learning next?373 You could either choose to start with an Access courses374or an open box module, which allows you to count your previous learning towards an Open University qualification.

Not ready for University study then browse over 1000 free courses on OpenLearn375 and sign up to our newsletter376 to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371