The television colour burst signal as a secondary frequency standard

The colour burst signals transmitted by the New Zealand television networks (TV1, TV2) are normally generated by rubidium vapour oscillators. While not primary standards, these oscillators are extremely stable and, provided they are calibrated, can serve as frequency standards. Every colour television receiver normally contains a quartz oscillator which is accurately locked in phase to the colour burst subcarrier and thus back to the rubidium vapour oscillator. Thus the colour burst subcarrier, available from any colour television set, is potentially a high quality frequency standard. The equipment used by the Physics and Engineering Laboratory to check this system is described, together with practical examples of the use of the colour burst subcarrier for calibration purposes.