Arrangement for both channel swapping and favorite channel features

The channel selection apparatus of a tuning system includes a present channel number register, a temporary register, a saved channel number register and a control unit for selectively controlling the three registers to (a) interchange the contents of the present and saved channel number registers when a swap key is activated, (b) enter the contents of the present channel number register in the saved channel number register without disturbing the contents of the present channel register when a favorite channel store key is activated, and (c) enter the contents of the saved channel number register in the present channel number register without disturbing the contents of the saved channel number register when a favorite channel recall key is activated.

The present invention pertains to the field of electronic channel selection 
apparatus as may be employed in a television receiver. 
U.S. Patent application Ser. No. 93,229 entitled "Receiver with a Channel 
Swapping Apparatus" filed Nov. 13, 1979, in the name of C. M. Wine, issued 
on June 2, 1981 as U.S. Pat. No. 4,271,532, discloses an electronic 
arrangement for selectively interchanging a presently selected channel 
with one previously selected by activating a single "swap" button provided 
for that purpose. Such an arrangement allows a user to conveniently and 
rapidly switch between two programs. Such an arrangement is therefore very 
useful, e.g., for allowing a user to contemporaneously follow the progress 
of two sporting events on two different channels. 
Since the swapping operation in the Wine arrangement, unlike prior swapping 
arrangements, is not activated by the selection of a new channel, it may 
also be used to store an originally selected channel while a number of 
other channels are selected during a search to determine if something more 
interesting than what is on the originally selected channel is available 
and then returning to the originally selected channel. However, since the 
starting point of such an operation in the Wine arrangement is storing the 
originally selected channel, it is not particularly well suited to 
immediately selecting a certain favorite channel without regard to the 
originally selected channel before a search. In other words, the Wine 
arrangement only permits the channel originally selected before a search 
to be immediately recalled. 
Thus, apparatus which enables a user to store and then unconditionally 
recall a favorite channel which is frequently watched is desirable, E.g., 
the use of cable converters and video tape and disk players has made a 
favorite channel feature particularly desirable since when such systems 
are used, the television receiver must be tuned to a predetermined 
channel, e.g., in the United States channel 03 or 04. In addition, since 
channel swapping and favorite channel features are different, apparatus 
which provides both features is also desirable. 
In accordance with one aspect of the present invention, in a tuning system 
including a present channel register for storing the channel number of a 
presently selected channel and a saved channel register for storing a 
previously stored channel number, favorite channel store and favorite 
channel recall means are provided for independently generating 
corresponding signals. Control means causes the contents of the present 
channel register to be entered in the saved channel register without 
disturbing the contents of the present channel register in response to the 
favorite channel store signal and causes the contents of the saved channel 
register to be entered in the present channel register without disturbing 
the contents of the saved channel register in response to the favorite 
channel recall signal. 
In accordance with another aspect of the present invention, channel swap 
means for generating a corresponding signal independently of the favorite 
channel store and recall signals are also provided. The control means 
causes the exchange of the contents of the present and saved channel 
registers in response to the channel swap signal.

In FIG. 1, a television receiver includes an RF output 1 for receiving RF 
carriers provided, e.g., by an antenna, video tape player or video disk 
player and a tuner 3 for heterodyning the received RF carrier to produce 
an IF signal. The IF signal is coupled to a signal processing portion 5 
for processing television signals in the conventional fashion to produce 
video and audio responses. 
Tuner 3 selects the RF carrier associated with a selected channel and 
generates a local signal, with which the selected RF carrier is 
heterodyned, having the appropriate frequency for the selected channel in 
accordance with the magnitude of a tuning voltage generated by a tuner 
control unit 7. Tuner control unit 7 converts binary signals representing 
the tens and units digits of the channel number of a presently selected 
channel stored in a register 9 to a corresponding tuning voltage. U.S. 
Pat. No. 4,031,549, entitled "Television Tuning System with Provisions for 
Receiving RF Carrier at Nonstandard Frequency", issued in the name of Rast 
et al. discloses a phase locked loop system suitable for use as tuning 
control unit 7 and is therefore incorporated by reference. A channel 
number display unit 11 is responsive to the binary signals stored in 
register 9 for displaying the channel number of the presently selected 
channel. 
A channel selection unit 13 generates the binary signals representing the 
channel number of the presently selected channel. Channel selection unit 
13 may, e.g., include a calculator-like keyboard having a key for each of 
the digits 0 through 9. In that case, after each the tens and units digits 
of a channel number have been entered, channel selection unit 11 generates 
four binary signals or bits (binary digits) encoded, e.g., in binary coded 
decimal (BCD) format, to represent the corresponding digit. When both 
digits have been entered, channel selection unit 13 generates a CHANGE 
signal which is applied to a load (L) input of register 9 through an OR 
gate 15. This causes the 8 bits representing the tens and units digits of 
the channel generated by channel selection unit 13 to be entered into 
register 9. Channel selection unit 13 may also include so-called "up and 
down channel scanning" keys for increasing or decreasing the channel 
number stored in register 9. "RCA Television Service Data Supplement for 
the CTC 101 Series Chassis", File 1980 C-7-S1, published by RCA 
Corporation, Indianapolis, Indiana, discloses a channel selection system 
for generating binary signals representing the channel number of a 
selected channel in response to the operation of digit keys or channel 
scanning keys and is therefore incorporated by reference. 
The present channel selection apparatus also includes registers 17 and 19 
and associated control logic 21 providing both channel swapping and 
favorite channel operations. Three pushbuttons SW, FS and FR are provided 
by which a user initiates channel swapping, the storage of a favorite 
channel and the recall of a favorite channel, respectively. Register 19 
stores the binary signals representing a channel number saved for swapping 
or as the favorite channel. Register 17 temporarily stores the binary 
signals stored in present channel register 9 before transfer to saved 
channel register 19 during the swapping operation and during the storage 
of a favorite channel. Control logic 21 includes a pulse generator 23 
responsive to clock pulses generated by an oscillator 25 for sequentially 
generating three pulses P1, P2 and P3 (see FIG. 3) on three respective 
lines and gating logic 27 for selectively routing pulses P1, P2 and P3 to 
present channel register 9, temporary register 17 and saved channel 
register 19 to control the transfer of a channel number depending on which 
one of switches SW, FS or FR has been operated. 
Each of switches SW, FS and FR comprises a normally opened momentary 
contact pushbutton switch, one terminal of which is connected to a source 
of positive voltage V+ corresponding to the "high" logic level. Circuitry 
for "debouncing" each one of switches SW, FS and FR, which is desirably 
provided to prevent the generation multiple rising and falling pulse edges 
as the contacts of a switch bounce, i.e., repeatedly close and open when a 
switch is first depressed, has been omitted from the Drawing for the sake 
of simplicity. Such "debouncing" circuitry is conventional and well known. 
When any of switches SW, FS or FR is closed, an OR gate 29 applies a START 
signal to pulse generator 23. As shown in FIG. 2, pulse generator 23 may 
simply comprise four cascaded D (data) type flip-flop stages and three AND 
gates 39, 41 and 43. With reference to FIG. 3, in response to the first 
clock pulse after the START signal goes "high", the Q output of first 
flip-flop 31 goes "high". Since the Q output of second flip-flop 33 is 
"high" at this time, the output of AND gate 39, which produces pulse P1, 
goes "high". In response to the second clock pulse, the Q output of second 
flip-flop 33 goes "high" and the Q output of second flip-flop 33 goes 
"low". As a result, the output of AND gate 39 goes "low". Pulse P2 and P3 
are generated in a similar manner. It is noted that only one sequence of 
pulses is generated per switch closure no matter how long one of switches 
SW, FS or FR is held closed as is indicated with reference to the duration 
of the START pulse. 
Delay elements 45, 47 and 49 generate "high" logic level pulses SW, FS and 
FR when respective ones of switches SW, FS and FR are closed. Pulse 
signals SW, FS and FR are coupled to gating logic 27 to control the 
routing of pulses P1, P2 and P3 to registers 9, 17 and 19. The durations 
of pulses SW, FS and FR are selected to be at least as long as the 
combined durations of pulses P1, P2 and P3 to ensure that pulses P1, P2 
and P3 reach the appropriate ones of registers 9, 17 and 19. As shown in 
FIG. 2, delay elements 45, 47 and 49 may simply comprise three respective 
S/R (set-reset) flip-flops set when respective ones of switches SW, FS and 
FR close and reset when the Q output of D flip-flop 37 goes "high" at the 
end of pulse P3. 
In operation, when switch SW is closed, the START signal is generated 
thereby initiating the generation of pulses P1, P2 and P3 and the SW pulse 
is generated thereby enabling AND gates 51, 53 and 55. Pulse P1 is routed 
through enabled AND gate 51 and an OR gate 57 to the load (L) input of 
temporary register 17. In response, the present channel number stored in 
present channel register 9 is entered into temporary register 17. Pulse P2 
is routed through enabled AND gate 53, an OR gate 59 and OR gate 15 to the 
load input of present channel register 9. In response, the saved channel 
number stored in saved channel register 19 is entered into present channel 
register 9. Pulse P3 is routed through enabled AND gate 55 and an OR gate 
61 to the load input of saved channel register 19. In response, the 
contents of temporary register 17 are entered into saved channel register 
19. At the end of these operations, the presently selected channel and the 
saved channel have been interchanged. 
When switch FS is closed, the START signal is generated thereby intiating 
the generation of pulses P1, P2 and P3 and the FS pulse is generated 
thereby enabling AND gates 63 and 65. Pulse P1 is routed through enabled 
AND gate 63 and OR gate 57 to the load input of temporary register 17. In 
response, the present channel number stored in present channel register 9 
is stored in temporary register 17. Pulse P2 is routed through enabled AND 
gate 65 and OR gate 61 to the load input of saved channel register 19. In 
response, the contents of temporary register 17 are entered in saved 
channel register 19. At the end of these operations, the presently 
selected channel has been saved for latter recall. 
When switch FR is closed, the START signal is generated thereby enabling 
the generation of pulses P1, P2 and P3 and the FR pulse is generated 
thereby enabling AND gate 67. Pulse P1 is routed through enabled AND gate 
67, OR gate 59 and OR gate 15 to the load input of present channel 
register 9. In response, the saved channel stored in saved channel 
register 19 is entered into present channel register 9. At the end of 
these operations, the previously stored channel has been recalled. 
The power for the channel selection apparatus within dotted line 69 is 
provided by a standby power supply 71. As a result, the contents of 
present channel register 9 and saved channel register 19 are maintained 
even when the receiver is in an off condition, i.e., when a power switch 
73 associated with a main power supply 75 of the receiver is in the off 
position. To prevent random data, which may not correspond to a legitimate 
channel number, from being entered in present channel register 9 and saved 
channel register 19 when the receiver is initially turned on after it is 
first plugged in, power up apparatus is provided for entering a 
preselected legitimate channel number into present channel register 9 and 
saved channel register 19 when the receiver is first plugged in. Power up 
apparatus for entering a preselected legitimate channel number into a 
present channel number register of an electronic tuner such as register 9 
is well known and may, e.g., comprise structure similar to that disclosed 
in RCA Service Data identified above and therefore need not be described 
in detail here. Briefly, such power up apparatus typically includes a 
power up detector for generating a power up pulse (PUP) when a standby 
voltage reaches a predetermined level and apparatus for entering the 
preselected channel in response to the PUP. To that extent, a power up 
detector 77 and a power up pulse generator 79 of the present selection 
apparatus cooperate for the same purpose and generate a first power up 
pulse PUP1 in response to which channel selection unit 13 enters a 
preselected channel number into present channel register 9. However, power 
up pulse generator 79 also sequentially generates second and third power 
up pulses, PUP2 and PUP3, respectively, after PUP1. Power up pulse 
generator 79 may be constructed in a manner similar to pulse generator 23 
or share components thereof or simply comprise three cascade monostable 
multivibrators. Second power up pulse PUP1 is routed through OR gate 57 to 
the load input of temporary register 17. In response, the preselected 
channel member stored in present channel register 9 is entered into 
temporary register 17. Third power up pulse PUP3 is routed through OR gate 
61 to the load input of saved channel register 19. In response, the 
contents of temporary register 17 are entered into saved channel register 
19. As a result of these operations, a preselected channel number is 
entered into both present channel register 9 and saved channel register 19 
when the receiver is first plugged in. 
While the present channel selection apparatus has been described with 
reference to a specific logic arrangement, it will be appreciated other 
arrangements providing the same or similar functions may be employed. 
E.g., the position of temporary register 17 may be moved to a position 
between the output of saved channel register 19 and the input of present 
channel register 9 as indicated by dotted line 81. In that case, during 
the channel swapping operation, pulse P1 is routed to the load input of 
temporary register 17 (in position 81), pulse P2 is routed to the load 
input of saved channel register 19 and pulse P3 is routed to the load 
input of present channel register 9; during the favorite channel storage 
operation, pulse P1 is routed to the load input of saved channel register 
19; and during the favorite channel recall operation, pulse P1 is routed 
to the load input of temporary storage register 17 and pulse P2 is routed 
to the load input of present channel register 9. 
It is noted that since only one pulse is needed to recall a favorite 
channel with the logic configuration first described and to store a 
favorite channel with the logic configuration described in the preceeding 
paragraph, any of pulses P1, P2 or P3 may be used for such purposes. In 
the same vein, since only two pulses are needed to store a favorite 
channel with the logic configuration first described and to recall a 
favorite channel with the logic configuration described in the preceeding 
paragraph, either one of pulses P1 or P2 and then the next one of P2 and 
P3 can be used for such purposes. 
It is also noted that if the swapping feature were omitted, temporary 
register 17 could be omitted and only a single pulse which was selectively 
routed to the load input of saved channel register 17 to store a favorite 
channel or to the load input of present channel register 9 to recall a 
stored favorite channel would be required. 
Further, while the present channel selection apparatus has been described 
with reference to user controls which are completely incorporated within 
the receiver for the sake of simplicity, it will be appreciated that the 
channel swapping and favorite channel storing and recalling feature may be 
incorporated in, and possibly more preferential in, a remote control 
system. In such case, channel selection unit 13 would include a remote 
control transmitter unit with a keyboard having digit and/or channel 
scanning keys and a remote control receiver unit with a decoder for 
entering a presently selected channel into present channel register 9 in 
response to the operation of the keys on the remote control transmitter 
unit as is in fact disclosed in the RCA Service Data referenced above. In 
such a remote control system, the keyboard of the remote control 
transmitter unit would also include the SW, FS and FR switches and the 
decoder of the remote control receiver unit would generate "high" level 
logic signals corresponding to respective switch closures for application 
to control logic 21. 
These and other modifications are intended to be within the scope of the 
present invention defined by the following claims.