JPS5784629A - Channel selection circuit - Google Patents
Channel selection circuitInfo
- Publication number
- JPS5784629A JPS5784629A JP55160296A JP16029680A JPS5784629A JP S5784629 A JPS5784629 A JP S5784629A JP 55160296 A JP55160296 A JP 55160296A JP 16029680 A JP16029680 A JP 16029680A JP S5784629 A JPS5784629 A JP S5784629A
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- output
- prescaler
- channel selection
- divider
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000010355 oscillation Effects 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J1/00—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general
- H03J1/0008—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor
- H03J1/0041—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor for frequency synthesis with counters or frequency dividers
- H03J1/005—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor for frequency synthesis with counters or frequency dividers in a loop
Landscapes
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Superheterodyne Receivers (AREA)
- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
Abstract
PURPOSE:To avoid beat interference, by making the output frequency higher than the intermediate freuency at all times and making it lower than the operation-enable-frequency of a programable divider, through the change in the frequecy dividing ratio of a prescaler in a channel selection circuit of a PLL system. CONSTITUTION:TV broadcast electromagnetic waves are supplied to a tunning circuit 2 via an antenna 1, whereby they are mixed with the output of a local oscillator 3 to output an intermediate frequency signal from a terminal 9. An oscillation frequency f of the oscillator 3 is frequency-divided with a frequency ratio 1/k preset with a control signal from a control circuit 8a at a prescaler 4a, the output is supplied to a programmable divider 5 and frequency-divided at a frequency-dividing ratio 1/N preset from the control circuit 8a, the output is compared in terms of phase at a phase comparator 6 with a frequency fr of a reference frequency generator 7, and the output becomes the controlled voltage input of the oscillator 3. Taking the frequency dividing ratio of the divider 5 as 1/N=kfr/f , the output frequency of the prescaler 4a is higher than the intermediate frequency, the harmonic is lower than the channel selection frequency and the beat interference can be avoided.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP55160296A JPS5784629A (en) | 1980-11-14 | 1980-11-14 | Channel selection circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP55160296A JPS5784629A (en) | 1980-11-14 | 1980-11-14 | Channel selection circuit |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS5784629A true JPS5784629A (en) | 1982-05-27 |
Family
ID=15711897
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP55160296A Pending JPS5784629A (en) | 1980-11-14 | 1980-11-14 | Channel selection circuit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5784629A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62159030U (en) * | 1986-03-31 | 1987-10-08 |
-
1980
- 1980-11-14 JP JP55160296A patent/JPS5784629A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62159030U (en) * | 1986-03-31 | 1987-10-08 |
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