e not supporting speech, it can be used on site. Mixed paging controls the slave oscillator frequency using varactor diodes. Table 45.4 Typical on site transmitter specifications Frequency range 25 to 54MHz 390 490MHz Frequency stability 10ppm from -10 to +55°C 5ppm from -10 to +55°C Output power 5 watts nominal 5 watts nominal RF load 500 nominal impedance, VSWR better than 2.1 500 nominal impedance, VSWR better than 2.1 Channel spacing 10/12.5/20/25kHz 20/25kHz, 12.5kHz Modulation type FM with FSK FM with FSK Modulation system Data F2D; Speech F3E Data F2D, F1D; Speech Data F2D; Speech F3E Data F2D, F1D; Speech Spurious emissions Better than 73dB (250nW) below carrier. 100kHz to 2GHz (excluding wanted and two adjacent channels) Line input -33dBm to -13dBm 600S balanced line Mains input 100V to 240V a.c. nominal 50/60Hz External transmitter -13dBm 600S speech and data outputs for modulation/control of a second transmitter control Back channel input TTL compatible for line transmission of data Line synchronisation Input/output for future installation of optional modules (P211 only) Master-slave Connectors provided for optional D.C. output 13.5V d.c. 50mA maximum for ancillary equipment Panel display (7 Standby transmitter keyed and transmitter failed segments) Internal LED indictors Phase-lock fail high reverse power and line sync fail Alarm outputs Open-collector logic outputs for transmitter keyed (on/off) and r.f. output (absent/present) Wide area paging 45/9 The telephone line interfaces from the master and to the slave will Table 45.5 Comparison of digital code formats be required to meet the national standard of the country in which the equipment is used. Some degradation in the S/N ratio (modulation on/modulation off) will occur from noise on the synchronisation line. Since the effective multiplication of the controlled crystal is Parameter POCSAG much greater in the h.f. band than in the u.h.f. band, a specification Code type Golay 32.12 BCH 32.21 BCH 31.16 of signal to noise ratio of 40dB at u.h.f. requi