This document discusses tuning range and tracking in electronics receivers. It defines tuning range as the frequency range over which a receiver can be adjusted using a tuning control. It explains that tracking ensures the local oscillator frequency precisely matches the signal frequency plus the intermediate frequency to avoid errors. There are different tracking methods, including padder tracking using a padder capacitor, trimmer tracking using a trimmer capacitor, and three-point tracking which combines both. Three-point tracking allows adjusting to eliminate errors at three frequencies for best accuracy.

1. Electronics & Telecommunication
Topics :- Tuning Ranges & Tracking
SUBMITED BYSUBMITED BY:-:-
VATSAL BODIWALA :140083112002
Under the Guidance :
Prof:- A.B.Bambhaniya
ET department, BVM
Birla Vishvakarma Mahavidhyalay

2. Content :-
Introduction of Tuning Range
Introduction of Tracking
 Dentition of Tracking
Types of Tracking
Padder Tracking
Trimmer Tracking
Three point Tracking

3. Definition of Tuning Range:-
“Tuning range is the frequency range over which a receiver, transmitter or
the other piece of equipment (such as antenna) can be adjusted by means of
a tuning control in consideration of required system performances.”
Receiver operating upto the limit of shortwave broadcasting i.e. 36 MHz.
 The 2 oscillators are used :-
1. Armstrong oscillator 2. Hartley oscillator
The colpitts & clap oscillator are used for still higher operating
frequencies.
 The frequency stability of the oscillator must be high .

4. Tracking :-
The receiver has a number of tunable circuits such as the antenna or mixer
or a local oscillator tuned circuits.
All this circuits must be tuned correctly if any station is to be tuned.
For this reason the capacitors in the various tuned circuits are
ganged(mechanically coupled to each other).
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5. Due to this arrangement it is possible to use only one tuning control to vary
the tuning capacitors simultaneously.
The local oscillator frequency (fo),must be precisely adjusted to a value
which is above the signal frequency(fs) by IF. i.e. fo=fs+IF
If this tuning is not done precisely then the frequency difference i.e.(fo-fs) is
not correct.
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6. This type of errors are known as the “tracking errors ”, because tracking
is a process in which the local oscillator frequency follows or tracks the
signal frequency to have a correct frequency difference.
Due to the tracking errors the stations will appear away from their correct
position on the frequency dial of the receiver.
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7. There are two types of Tracking.
1)Two Point tracking
Padder Tracking
Trimmer Tracking
2) Three point Tracking
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8. Padder Tracking
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9. A Small variable capacitor Cp called as the padder capacitor is
connected in series with the oscillator coil.
Due to the series connection of Cp andCosc the effective
capacitance will be less than Cosc alone.
This will increase the oscillator frequency making the tracking
error positive.
The padder capacitor is adjusted to have zero tracking error on
two extrme points on the frequency dial.
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10. Error in padder tracking
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11. Trimmer Tracking
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12. A small variable capacitor CTr called as the trimmer capacitor is
connected in parallel with the main capacitor Cosc .
Due to parallel connection of CTr and Coscthe effective
capacitance will be greater than cisc alone.
This decreases the oscillator frequency making the error
negative.
The Trimmer is adjusted to get zero error at two points on the
frequency dial.
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13. Error in Trimmer Tracking
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14. Three point Tracking
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15. This combines the padder and trimmer tracking.
The three frequencies of correct tracking i.e. at which zero
tracking error exists are normally 600 KHz,1500 KHz and the
geometric mean of the two i.e.950 KHz.
It is possible to keep the tracking error below 3 KHz.
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16. Associated Tracking Error
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17. References:
Tech-max:- J.S.KARTE
Wikipedia.com
Slide share.com