# Analog remote control signal's threshold voltage, length and delay

I do not have too much knowledge background of RF knowledge.

Background:

I am using Arduino board to record and interpret RF analog signals. There is an 10-bit analog-to-digital converter.

Questions:

1. I saw many people use "threshold voltage" to describe the levels of analog signals (convert to digital). In the case of Arduino's 10-bit ADC, it is level 1-1024.

So what this "threshold voltage" actually refer to (e.g. strength of analog signal or something else)?

2. Continue Q1. If the threshold is low than certain value (e.g. 80), it is defined as LOW signal. Similarly, HIGH signal for threshold higher than 100.

For example, remote control signal (e.g. air-condition) consist of a series of (LOW, HIGH) pairs. This is what I saw from some Arduino projects. Is it a common way to define LOW and HIGH signal?

3. What means the length of analog signal? Time?

4. If you convert digital signal back to analog signal, and send them through a transmitter. You need to set certain delay between each (LOW, HIGH) pair. Why there is such delay?

• Q1/2: You're confused between a number of things. In the analog world, a defined threshold is meaningless - it's just a choice you make to say something is high or low depending on your application. Threshold in digital refers to the actual voltage a gate will change or be indeterminate. 3. Yes, time. 4. Would need to know more about your setup. Commented Oct 31, 2017 at 7:27
• @awjlogan: I understand Q1-3 already. For Q4, this is the application arduinobasics.blogspot.sg/2014/06/…. it said "the signal alternate between LOW and HIGH" is this common for RF remote control? Commented Oct 31, 2017 at 7:35
• If you understand Q1 to 3 already why put them in the question so people spend time answering them? Commented Oct 31, 2017 at 7:42
• Q4 then. Yes, the output from a remote is a digital signal (HIGH = ON, LOW = OFF) usually using Manchester encoding. Reason being that the signal to noise is much better than an analog signal. It is usually modulated as well to reduce the effects of ambient light. Commented Oct 31, 2017 at 7:59
• @awjlogan: very clear! Commented Oct 31, 2017 at 8:01