The present invention relates to coding of audio signals, and in particular to high frequency reconstruction methods including a frequency domain harmonic transposer. A frequency-to-PWM circuit is coupled to the input node to provide second PWM signals having a duty cycle corresponding to the rotational speed of the motor. Each pixel further includes a thermoelectric heat transfer circuit which transfers heat to or from the sensor in an amount which varies in response to the video signal. The infant seat detachably is installed on the seat tube.