the following specifications for a 70 cm screen at 27 5 kv a yoke with a high inductance has high sensitivity mm a and requires only a small driving current the resonant frequency of the resonant circuit formed by the yoke and parasitic capacitances will decrease with increasing coil inductance this resonant frequency has to be at the least higher than the video bandwidth to ensure correct bsvm operation the inductance value is chosen as a compromise between these two contradictory requirements the auxiliary yoke signal should coincide within u00b1 30 nsec with the video signal at the picture tube cathode the delay of the video signal from the take off point to the cathode will be about 60 nsec in a 100 hz field frequency receiver the delay of the proposed bsvm circuit amounts to about 75 nsec high frequency noise for example greater than 10 mhz will be accentuated in the bsvm signal due to the differentiator since the auxiliary yoke is driven by a collector and becomes more resistive with increasing frequency this noise will cause radiation in the lower frequency bands this can be avoided by bypassing the high frequency currents with a capacitor c4 connected in parallel to the yoke as long as only frequencies over 10 mhz are bypassed correct bsvm is maintained since the video signal has a bandwidth of only 10 mhz however capacitor c4 and the yoke and parasitic capacitances form a parallel resonant circuit with a resonant frequency of about 9 mhz therefore a damping resistor r9 is connected in parallel with the yoke to avoid resonant currents these currents would produce.