3

Preliminary Information

SATURN

Description

ENAVLE STARTUP

MODE CDMA BAND 1900

Conditions

Standby Mode

0

0

X

X

All circuits powered down

except logic inputs

Start up Mode

0

1

X

1

For high band IF

(210.38MHz)

0

1

X

0

For low band IF (85.38MHz)

Turns on VCO circuits, DLL

quadrature generation,

prescaler and IQ

demodulator. All other

circuits remain powered

down

CDMA mode

1

1

1

1

For high band IF

(210.38MHz)

1

1

1

0

For low band IF (85.38MHz)

All circuits operational

except for IF output buffer,

CDMA input stage selected.

FM Mode

1

1

0

0

All circuits operational

except for IF output buffer,

FM input stage selected.

Alternative FM mode

1

1

0

1

Note 4

CDMA IF AGC

1

0

1

X

Demodulator and LO

only mode

generation circuitry powered

down. IF output buffer

enabled

FM IF AGC

1

0

0

X

Demodulator and LO

generation circuitry powered

down. IF output buffer

enabled.

X = Don’t Care

Notes

1.

STARTUP mode is provided to allow VCO/DLL/prescalers to stabilise before signal path is activated. This is a power-saving

feature since the signal path is redundant during this period. If this feature is not required, the ENABLE and STARTUP

control pins can be shorted together so that all circuitry is activated at the same time.

2.

In high band mode (Band 1900 = 1) the VCO operates at twice the IF frequency. For example if IF = 210.38MHz then the

oscillator operates at 420.76MHz. A delay locked loop (DLL) circuit then generates the quadrature LO signals. The prescaler

output, VHFBUF, is VCO frequency divided by 8 (52.494MHz).

3.

In low band mode (Band 1900 = 0) the VCO operates at 4 times the IF frequency. for example if IF = 85.38MHz the oscillator

operates at 341.52MHz. This is then divided and uses DLL circuit to provide the quadrature LO signals. The prescaler output,

VHFBUF, is VCO frequency divided by 8 (42.69MHz).

4

This mode can be used for FM. The VCO operates at twice the LO frequency. This mode is not normally used as a large

tuning range is required on the VCO. Prescaler output is LO frequency divided by four.