******************************************************************************* * CB RADIO MODIFICATIONS and PLL INFORMATION * ******************************************************************************* * The information contained within this bulletin is for educational purposes * * only and is not intended as an endorsement of any particular practice. The * * owners/operators of this BBS assumes no liability with respect to the use of* * the information contained herein. We do not encourage illegal use of * * modified radios on any band of the spectrum. Heavy penalties result if you * * are caught using illegal, non-allocated frequencies not approved by the * * DOTC... * ******************************************************************************* * by Wayne Simpson (SYSOP HH-BBS). * ******************************************************************************* **** INTRODUCTION ************************************************************* ------------------------------------------------------------------------------- The Phase-Locked-Loop or "PLL" Frequency Synthesizer used in CB radio's is a marvelous device. It can generate all the signals needed to run a complex transceiver, is more accurate than Crystal Control, and more reliable because fewer parts are needed. However understanding it's operation seems to cause a lot of anxiety among CB operators as well as professional technicians. Anybody that is interested in the Technical side of CB radio or the PLL process of operation will get a lot of interesting reading from this bulletin. **** WHY PLL IN CB ??? ******************************************************** ------------------------------------------------------------------------------- The main reason for the development of PLL synthesizers was the American CB service expansion from 23 to 40 channels in 1976, and the Australian 23 to 18, then to 40 channel expansion around the same time. In the day's of 23 channels, just about all CB radio's had their frequencies controlled by a Crystal Synthesiser. By electronically combining the signals of 2 or 3 quartz crystal oscillators in a common 'Mixer', all the various Receive/Transmit signals (which are not normally the same) could be created with only 12 or 14 Crystals for AM and a few more for SSB. This provided great savings to the manufacturers of the Radio equipment in Cost, Circuit Complexity and space, because otherwise at least 46 different quartz crystals would be needed, one pair per channel. There wasn't enough quartz left in the world to give to all the CB manufacturers; they had to leave some for all of those cheap $4.00 watches! With CB interest growing very rapidly, new methods were required because of the increased number of legal channels. Manufacturers designers had to figure out how to generate a large number of signals with a minimum of parts, space, complexity, and of course, cost. The answer was the PLL synthesiser. **** PLL IC FUNCTION TERMS **************************************************** ------------------------------------------------------------------------------- VCC or VDD. ---------- This is the +DC supply voltage which atually provides the operating power to the chip, and is generally in the range of 4 to 8 Volt's. GND or VSS. ---------- This is the DC power ground connection for the above. NOTE:- A chip may be found one or more of its functional pins tied to either of the above sources. This may be done to enable a specific function by connecting that function to a logic 1 or 0, or to prevent an unused function pin from "floating" unconnected to prevent a possible change in it's logic state. RI ---- Reference Oscillator Input. This is where the (usually) 10.240 MHz crysal is connected. Crystal pins are sometimes called "X" by the manufacturer. RO ---- Reference Oscillator Output. In most chips the crystal is simply connected across RI and RO because the chip has an inbuilt oscillator circuit which only requires some external capacitors. However, some chips such as the PLL02A don't have the built in oscillator; that is why there is no RO pin and an active transistor oscillator is required externally which connects to RI. 1/2R ------ A built-in divide by two circuit which provides an output of half the 10.240MHz reference oscillator frequency, or 5.12MHz. If used, it normally connects to a trippler circuit to provide a 15.360MHz signal (5.12MHz * 3) which can be used for loop mixing with the 16MHz VCO. This mixing provides a low frequency signal input or downmix to the programmable divider. RB ---- Buffered Output of the 10.240MHz Reference Oscillator. This signal, if present, can be used for mixing with the 10.695MHz receiver first IF or mixing with the 16MHz VCO during TX mode to provide the 455KHz second IF (RX) or the direct on-channel TX Frequency. Fin ----- Input to the programmable divider which is coming from the output of the VCO. Sometimes called "PI"(Programmable Input) or "DI"(Divider Input) by some manufacturers. This is the actual downmix signal or direct VCO signal in the faster chip's which will be compared to the reference dividers output in the Phase Detector. It is the change in the signals frequency which forces the Phase Detector and VCO to correct until the loop lock's. DO ---- Phase Detector output. Sometimes called "PO" or "PDout"(Phase Output) or "EO"(Error Output) by some manufacturers. This is the output which results from comparing RI and Fin. If the two inputs dont match exactly, this circuit sends a DC correction output to the loop filter/VCO until the loop corrects itself and locks up. LD ---- Lock Detector. Sometimes called "LM"(Lock Monitor) by some manufacturers. This is a second output of the phase detector which is used to kill the transmitter (and sometimes the receiver) if the loop is not locked and operating correctly. Some chips have more than one lock detector and sometimes you will see LD1 and LD2 on the specifications. When two lock detectors are used, their normal outputs are usually opposite logic states. This is a convenient design feature which allows the manufacturer some flexibility because he can have a choice of inhibiting circuits ; some work with LOW outputs and some work with HIGH outputs. Some radio's use both LD pins in their circuits. MC ---- Misprogram Code Detector. The same idea as the Lock Detector, this is found in the newer ROM Chip's. If you try to force an illegal program code on the chip, this pin is activated and will kill the transmitter, receiver, or in some cases, call up channel 9 or channel 19 instead. T/R ----- Transmit/Receive switch. This is used to provide the 455KHz offset for the receiver's second IF stage in dual conversion AM or FM radio's. Pressing the Mike Button changes the pins logic state to its opposite state from the RX mode. This shifts the ROM controlling the programmable divider, and in some chips also shifts the output of the reference divider from standard 5KHz steps to 2.5KHz steps. The T/R shift is the reason you will see two different sets of 'N' codes and VCO frequencies in a radio's service manual or SAMS FOTOFACTS. NOTE:- Some manufacturers chip specification sheets show a bar (-) above the pin functions, such as LM, T/R, etc. This bar is a digital logic symbol which indicates what state ( 1 or 0 ) that pin is when activated. FS ---- Frequency Select. This is a feature of some chips which allows them to synthesize frequencies in either 10KHz CB steps, or 5KHz steps. Remember, some older chips such as the PLL02A were intended for other uses besides CB, such as VHF marine radio's, Aircraft radio's, etc., where the 5KHz channel spacing is common. In addition, this feature often makes it easier to synthesize SSB frequencies as well as AM and FM although the feature has not been used much for this. Depending on whether the Chip has an internal pull-up or pull-down resistor here, it is generally connected to produce 10KHz spacings in the older chips. The newer chips having a T/R shift must use the 5KHz spacing when the T/R pin is also used. IMPORTANT:- You can not use this function to get 5Khz channel spacings, because the Programmable Divider must also change to match the spacing. AI,AO ------- Active Loop Filter Amplifier Input and Output. This circuit, if present, is used to smooth out the digital waveform coming from the phase detector, before it is applied to the VCO. This filter is found in the newer CB-only chips. The older chips Eg(PLL02A) require external passive filters using capacitors and resistors. In many radio's you will find that these pins are connected either directly or through a resistor so that they are placed in series between the phase detector output pin and the VCO input. FIL ----- Active Filter. Where using this designation in certain very old chips when the exact specification sheets are not available but its known from studying the chips that wiring in the radio that the pins are in fact part of a loop filter. T&Q ----- This is a wave shaping circuit found in a few NEC chips (uPD2810, uPD2814, uPD2816, uPD2824). It adds design flexibility but is often not even connected. This circuit consists of an input amplifier and a "flip flop", and its purpose is to change a sine-wave input (T) to a square wave output (Q) which is more compatible with a digital electronic circuits. P0..to..P10 ----------- Program select pins from the channel switch. (Sometimes called "D" for "DATA" rather than "P" for "PROGRAM".) These pins control the actual channel selection. They may control selection through straight binary coding, BCD, or ROM. The sub numbers indicate the weight or significance of each pin. For example if there were eight programming pins, P1 to P8, P1 would be in the "least significant bit" and P8 would be the "Most significant bit". The higher the sub number, the greater the weight of the pin. NC ----- No Connection. An unused pin. May actually be disconnected inside the chip, or simply not be used for that particular radio's PLL circuit. * --- Special Remarks when necessary. **** PINOUT'S of POPULAR PLL IC'S ********************************************* ------------------------------------------------------------------------------- CCI3001 ------- Popular in models (Pace 8093,8193, Royce 582/651,639/642, SBE LCMS-4 and the SommerKamp TS310DX.) Pin1 = Fin Pin18 = FIL Pin2 = Vdd Pin17 = FIL Pin3 = RI Pin16 = P0 Pin4 = RO Pin15 = P1 Pin5 = Vss Pin14 = P2 Pin6 = AO Pin13 = P3 Pin7 = AI Pin12 = P4 Pin8 = ** Pin11 = P5 Pin9 = PD Pin10 = T/R* *R = 1, T = 0. Shifts down 455KHz in transmit mode. **Control used to turn off one mixer IC input between TX and RX. ( Obsolete chip using binary inputs and internal ROM ). ------------------------------------------------------------------------------- CC13002 ------- Popular in models (Kraco 2410, Pace 8003, Royce 607, SBE LCM-8P and Realistic TRC209-18.) Pin1 = NC Pin18 = *** Pin2 = Vss Pin17 = ** Pin3 = VCO Pin16 = Vss Pin4 = VCO Pin15 = Vdd Pin5 = T/R* Pin14 = P0 Pin6 = PD Pin13 = P1 Pin7 = P5 Pin12 = P2 Pin8 = P4 Pin11 = P3 Pin9 = RI Pin10 = RO *R = 1, T = 0 **27MHz out to TX Amplifiers. ***17MHz out to RX Mixer. ( Obsolete chip using binary inputs. Unique in that it contains its own mixer for the VCO.) ------------------------------------------------------------------------------ HD42851 (Hitachi). ------------------ Popular in Models ( Sharp CB5470 SSB.) Pin1 = P1 Pin24 = MC (usually unconnected) Pin2 = P2 Pin23 = Vss Pin3 = P3 Pin22 = LD** Pin4 = P4 Pin21 = PD OUT Pin5 = P5 Pin20 = AI Pin6 = P6 Pin19 = AO Pin7 = P7 Pin18 = PDin from PROG.DIV Pin8 = P8 Pin17 = REF DIV. OUT Pin9 = 1/2R Pin16 = PDin from REF. DIV Pin10= RI Pin15 = PROG DIV.OUT. Pin11= RO Pin14 = FS* Pin12= Vdd Pin13 = Fin CC13002 ------- Popular in models (Kraco 2410, Pace 8003, Royce 607, SBE LCM-8P and Realistic TRC209-18.) Pin1 = NC Pin18 = *** Pin2 = Vss Pin17 = ** Pin3 = VCO Pin16 = Vss Pin4 = VCO Pin15 = Vdd Pin5 = T/R* Pin14 = P0 Pin6 = PD Pin13 = P1 Pin7 = P5 Pin12 = P2 Pin8 = P4 Pin11 = P3 Pin9 = RI Pin10 = RO *R = 1, T = 0 **27MHz out to TX Amplifiers. ***17MHz out to RX Mixer. ( Obsolete chip using binary inputs. Unique in that it contains its own mixer for the VCO.) ------------------------------------------------------------------------------ HD42851 (Hitachi). ------------------ Popular in Models ( Sharp CB5470 SSB.) Pin1 = P1 Pin24 = MC (usually unconnected) Pin2 = P2 Pin23 = Vss Pin3 = P3 Pin22 = LD** Pin4 = P4 Pin21 = PD OUT Pin5 = P5 Pin20 = AI Pin6 = P6 Pin19 = AO Pin7 = P7 Pin18 = PDin from PROG.DIV Pin8 = P8 Pin17 = REF DIV. OUT Pin9 = 1/2R Pin16 = PDin from REF. DIV Pin10= RI Pin15 = PROG DIV.OUT. Pin11= RO Pin14 = FS* Pin12= Vdd Pin13 = Fin *1 = 10KHz steps, 0 = 5KHz steps. **1 = Locked, 0 = Unlocked. The latest AM/FM type chip that's easy to mistake for the uPD861 as the pinout is almost identical. With Pin 14 LOW, N-Code is pure 8 bit binary with a range of 'N' = 53 to 308. With Pin 14 HIGH, range of 'N' = 3 to 191. If Pin 14 is high and Pins 7 and 8 are LOW, programming is in BCD with standard 'N' Codes of 91 to 135. Many internal functions have been brought out to IC pins for easier trouble shooting. ------------------------------------------------------------------------------ C5121 ----- Popular in Models ( Contact 40FM, GE 3-5909A, Midland 77-155, Pace CB8001, Regency CB-1&2.) Pin1 = SEG-A Pin22 = LED BAR/GRAPH, MUX OUT. Pin2 = SEG-B Pin21 = NC Pin3 = SEG-C Pin20 = STEP*** Pin4 = SEG-D Pin19 = CH.9 Pin5 = SEG-E Pin18 = T/R** Pin6 = SEG-F Pin17 = LD* Pin7 = SEG-G Pin16 = PD OUT Pin8 = Vss Pin15 = AI Pin9 = RI Pin14 = AO Pin10= RO Pin13 = Vdd Pin11= Vss Pin12 = Fin *1 = Locked, 0 = Unlocked. **1 = TX, 0 = RX. ***1 = STEP UP, 0 = STEP DOWN. The latest AM/FM typr chip, identical in mixing to the TC9109 on page 104. Note this one uses a single data bit to step up or step down, eliminating the expensive BCD type Channel Selector switch. Like the SM5123A/SM5125B, this contains the LED drivers within the chip. (NOT EASILY MODIFIED). ----------------------------------------------------------------------------- LC7110 (SANYO). --------------- Popular in Models ( GE 3-5804A,5871B, Realistic TRC454-TRC470, Sanyo TA2000-TA4000-TA6000. ) Pin1 = Vdd Pin20 = Vss