Racal Instruments 9916 User Manual

GENERAL CIRCUIT FUNCTIONS
- 3.2 Outside the COl Chip, other circuit functions are carried out, as follows:-
(a) Input ampl ification and signal shaping. AGC and overload
protection. Input (channel) selection.
(b) An eight-digit display system in bit-parallel byte serial (mul tiplex)
form, with data readout available for external use.
(c) Clock (reference) frequency generation using a discrete 5 MHz
oscillator circuit, or a high-stability temperature controlled
oscillator. The reference frequency is doubled to 10 MHz for use
in the COl Chip.
(d) The power supply system operates from either a. c. I ine power or an
optional battery pack using re-chargeable nickel-cadmium cells.
Trickle charge and full charge facilities are included. 'Charge' and
'Battery Low' indicators are provided. Suppl ementary power supply
circuits provide +24V for the 'A' ampl ifier and +2V for the COl Chip.
A 'battery economy' facility is provided.
(e) The BURST facility employs circuits which put the counter into the
Hold condition with blanked out display. The incoming signal then
automatically resets the counter and allows a single measurement to
be made and held.
DYNAMIC DISPLAY SYSTEM
3.3 The Display Assembly contains an eight-digit display using light-emitting
diodes. as numerical indicators. These indicators are driven by b.c.d. data
,rom the CD I Chip, via a seven-segment decoder. Each displayed numeral is formed by
_ I ighting an appropriate number of short straight segments. The numeral '8', for example,
IS formed from 7 segments, whereas the numeral '4' will require only 4 segments.
3-2
9916 Vol. 2

Racal Instruments 9916 Specifications

General

Brand	Racal Instruments
Model	9916
Category	Measuring Instruments
Language	English