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1 2GHz VCO With Linear Modulation - Since high recurrence voltage-controlled oscillators, or VCOs, are difficult to develop, Maxim has created an incorporated 1.2GHz oscillator, the MAX2754. The middle recurrence is set utilizing the TUNE data, and a straight balance info permits the recurrence to be adjusted. The IC is accessible in a 8-pin µMAX bundle, works from a supply of between 2.7 V and 5.5 V, and draws a current of under 2 mA. Both TUNE and MOD work over control voltage scope of +0.4 V to +2.4 V. TUNE permits the VCO recurrence to be balanced from 1050 MHz to 1270 MHz. In a few applications a PLL control voltage will be connected here, permitting the inside recurrence to be set precisely to a sought quality.

For straightforwardness in the circuit outline we have demonstrated a potentiometer. The MOD data permits the VCO to be regulated in an advanced or simple style, with an exchange incline of –500 kHz/V. In the circuit we have demonstrated an illustration where MOD is utilized for recurrence movement keying (FSK) adjustment. Resistors R1 to R4 shift the level of the information flag with the goal that it has a middle estimation of +1.4 V and an adequacy comparing to the wanted recurrence deviation.

One case set of qualities, suitable for use with a 5 V power supply, is as per the following: R1 = 480 Ω, R2 = 100 Ω, R3 = 220 Ω und R4 = 270 Ω. The data impedance is around 1 kω. The yield level of the MAX2754 at OUT is around –5dBm into 50 Ω. A coupling capacitor is not required here: the IC as of now contains one. The MAX2754 is intended for use in transmitters in the 2.4GHz ISM (mechanical, experimental and therapeutic) band. This requires the expansion of a recurrence doubler, which, alongside the 2.4GHz recieving wire, is indicated typically in the circuit.