Lie great number of lies, depending on how the political wind blows." The question of whether lies can reliably be detected through nonverbal means is a subject of some controversy. Polygraph "lie detector" machines measure the physiological stress a subject endures in a number of measures while he/she gives statements or answers questions. Spikes in stress are purported to indicate lying. The accuracy of this method is widely disputed, and in several well-known cases it was proven to have been deceived. Nonetheless, it remains in use in many areas, primarily as a method for eliciting confessions or employment screening. Polygraph results
Product detector Product detector A product detector is a type of demodulator used for AM and SSB signals. Rather than converting the envelope of the signal into the decoded waveform like an envelope detector, the product detector takes the product of the modulated signal and a local oscillator, hence the name. A product detector is a frequency mixer. Product detectors can be designed to accept either IF or RF frequency inputs. A product detector which accepts an IF signal would be used as a demodulator block in a superheterodyne receiver, and a detector designed for RF can be combined with an RF