Television tuning system with electronic frequency adjustment apparatus

A tuning system for a receiver for selecting one radio frequency (RF) signal of a plurality of receivable RF signals comprising:

• RF means having an adjustable frequency selective characteristic for receiving said RF signals;
• oscillator means for developing an oscillator signal, the frequency of which is controlled by a first control signal for selecting said one RF signal;
• one of said RF means and said oscillator means including a trimming element responsive to a trimming signal;
• mixer means for heterodyning RF signals from said RF means and said oscillator signal to develop an intermediate frequency (IF) signal at a predetermined frequency;
• first control means for developing said first control signal for selecting said one RF signal so that said one RF signal is shifted in frequency to said predetermined IF frequency by said mixer means;
• second control means for developing said trimming signal having different predetermined magnitudes corresponding to groups of adjacent ones of said RF signals including
• memory means for storing said trimming signal;
• and
• means for applying said trimming signal to said trimming element of said one of said RF means and said oscillator means.

In a tuning system for a receiver for selecting one radio frequency (RF) signal of a plurality of receivable RF signals including

• filter means for receiving said RF signals,
• oscillator means for developing an oscillator signal, the frequency of which is controlled by a first control signal developed for selecting said one RF signal, and
• mixer means for heterodyning said RF signals from said filter means and said oscillator signal from said oscillator means to translate said one RF signal to a predetermined intermediate frequency;
• means for adjusting the frequency selective characteristics of said filter means comprising:
• tuning means included within said filter means for tuning its frequency selective characteristics responsive to second and third control signals;
• memory means having a plurality of memory locations for storing coded signals representing values of said second control signal corresponding to at least respective groups of said receivable RF signals, and representing values of said third control signal unaffected by selection of said one RF signal;
• address means for addressing said memory location corresponding to the selected said one RF signal in response to the selection thereof;
• and
• conversion means for developing said second control signal from the coded signal stored in said addressed memory location, for developing said third control signal from the coded signal stored in the memory location therefor, and for applying said second and third control signals to said tuning means to effect said tuning.

A tuning system for a receiver for selecting one radio frequency (RF) signal of a plurality of receivable RF signals comprising:

• RF means having an adjustable frequency selective characteristic for receiving said RF signals;
• oscillator means for developing an oscillator signal, the frequency of which is controlled by a first control signal for selecting said one RF signal;
• mixer means for heterodyning RF signals from said RF means and said oscillator signal to develop an intermediate frequency (IF) signal at a predetermined frequency;
• first control means for developing said first control signal for selecting said one RF signal so that said one RF signal is shifted in frequency to said predetermined IF frequency by said mixer means;
• tunable circuit means included within said RF means for adjusting its frequency selective characteristic in response to an adjustment signal;
• and
• means for developing said adjustment signal including:
• memory means for storing and developing a first component of said adjustment signal, said first component having a plurality of values corresponding to respective groups of adjacent ones of said RF signals,
• means for developing a second component of said adjustment signal in response to selection of said one RF signal,
• means for combining said first and second components to develop said adjustment signal and for applying said adjustment signal to said tunable circuit means for effecting said adjusting of said frequency selective characteristic.

A tuning system for a receiver for selecting one radio frequency (RF) signal of a plurality of receivable RF signals comprising:

• oscillator means for developing an oscillator signal having a frequency controlled by a control signal;
• mixer means to which said receivable RF signals and said oscillator signal are applied for heterodyning said receivable RF signals to develop an intermediate frequency (IF) signal;
• first control means for developing said control signal so that said IF signal includes said one RF signal shifted to a predetermined frequency;
• IF circuit means to which said IF signal is applied for passing said IF signal, said IF circuit means including tunable circuit means for limiting the bandwidth of said passed IF signal, and including a trimming element for trimming said bandwidth responsive to a trimming signal;
• second control means for developing said trimming signal including:
• memory means for storing and developing said trimming signal having a predetermined magnitude selected for trimming said bandwidth to a predetermined bandwidth which includes said predetermined frequency, and
• means for applying said trimming signal to said trimming element of said IF circuit means.