AboutDave Nyce Expertise I have been an electronics engineer for 25 years. I can answer questions on analog and digital circuits and my specialty is sensors.
Experience I am the inventor on 23 US patents, and also some foreign ones. Developed sensors for over 25 years. Licensed private pilot (airplane and rotorcraft), have HAM radio license. I'm not an expert in computer networking.
Question My 12-year old daughter wants to test the hearing range of her pets for the science fair. I have an HP 204c Audio Oscillator, but the animals don't react to a sine wave. I am electronically ignorant and want to know if there is any way to connect a tape player to this device to product actual words (the animals name) at up to 70000khz? Please help!!!
Answer I'm afraid that it might be a little more difficult than it may seem. A sine wave can have a particular frequency, because it has the same rate of change throughout. If you use another waveform, however, it has a large range of frequencies over which energy is present. You would need a spectrum analyzer to actually know what frequencies are being produced. Also, a tape player has very little capability above 15,000 Hz. I can envision two possible ways to accomplish your hearing test:
The easiest way would be to train the animal to notice the sound from the speaker that is connected to the sine wave oscillator. This is easy with a dog, but may be difficult with other annimals.
The only way I can say offhand to make "speech" with a higher frequency of a controlled frequency range, is to make the voice signal into an amplitude control of a carrier frequency. The carrier frequency would be the controlled sinewave from your oscillator. You would make a microphone signal control the base of a transistor, for example, while the collector voltage was capacitively coupled to the sine wave. Then the resulting ouptut signal from the transistor collector circuit would need to be amplified in order to drive a speaker. Unfortunately, this would need you to enlist the help of someone who knows electronics.
I can provide you these ideas, but I don't have the time available on this website to design the circuits for you.
I did an experiment when I was in school to test the hearing range of the students, parents, and teachers. She might try this instead. There is a large variation in general hearing range depending on sex, age, and occupation. For this, you can use your oscillator and a speaker.
