Dual
The type 74 dual ppm indicator embodies two fast moving coil movements, similar to those used in the Sifam single-movement ppm indicators concentrically mounted, one in front of the other, in a single matt-black case . Performance conforms to the latest BBC specification ED1542 and to BS/IEC standards where relevant.
There are two variants: type A which has one yellow and one white pointer; type B which has one red and one green pointer.
The yellow, red and green pointers are fluorescent. Each pointer operates on a common scale which has white markings on a black dial. Alternative scales can be provided.
Alternative scales
Two scale designs are available in accordance with BS 5428:Part9:1981: and IEC 268-10A: Part 10:1978. Scale type IIa has size approximately equal divisions- each representing 4dB relative to reference mark ‘6’ on the scale. An alternative, type IIb scale (which also conforms to the European Broadcasting Union ppm indicator standard) has twelve 2dB divisions and is numbered -12db to +12db at 4dB intervals, but with an additional mark at reference point +9dB, The range is, therefore, -21dB to +3dB relative to reference mark +9dB.
Illumination
The type 74 dual ppm indicator is provided with a window in the top of the case to allow for external illumination by the customer when this is required.
Dual VU meters can also be supplied.
Models
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74PPM |
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R74VU |
