10

Reference:

BBC Micro analogue in

A custom connector would be required between this D-shape rows of pins port and a standard input socket for phono/rca or 3.5inch or 1/4inch jack.

What would be the bit depth and sampling rate?

2 Answers 2

15

No, it can not be used to sample audio.

As the link you provided says, in 12-bit mode it takes 10 milliseconds to convert a sample, and even in 8-bit mode it takes 4 milliseconds.

That results into maximum sampling rate of 250 Hz, which is useless for sampling audio.

The low sampling rate indicates the analog input is meant for slowly changing signals, like sampling a paddle position, and it can be used for datalogging something that changes slowly enough like temperature.

2
  • Yup, I believe it was intended for attaching a pair of two-axis joysticks or paddles. These days four-axis joysticks are more common, and it could be used to attach one of those.
    – Chromatix
    Apr 2, 2021 at 18:21
  • @Chromatix Joysticks and paddles were common, but a number of schools and universities connected sensors to the analogue port, to sample data from experiments (as mentioned in the answer). There were also robots / vehicles that used the analogue port. For examples, see link.springer.com/chapter/10.1007/978-1-349-07644-4_3 , computinghistory.org.uk/det/53106/BBC%20Buggy
    – Kaz
    Apr 3, 2021 at 13:28
0

In the early 80s, a friend an I did use it for sampling audio, but in conjunction with his audio equipment to play the audio back more slowly. The quality wasn't really useable, so the previous answer is probably corrent!

3
  • I too did this in an attempt at voice control; the low conversion rate meant that I could capture the approximate amplitude of the speaker’s voice but not the harmonic/frequency components. Short answer is no.
    – Frog
    Jul 21, 2021 at 10:47
  • There were command recognition systems that used this method with a very small dictionary of words with fairly different volume characteristics. Jul 22, 2021 at 14:29
  • That was the problem- it was possible to measure volume but not harmonic content. Differentiating between ’yes’ and ‘no’ being a typical example.
    – Frog
    Jul 22, 2021 at 19:55

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